diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4b5f788b..ea731ce5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -54,6 +54,22 @@ jobs:
           cd /review
           /hyperstyle/bin/pytest
 
+  type-checking:
+    name: Type checking
+    runs-on: [ self-hosted, small ]
+    needs:
+      - build_image
+    container:
+      image: hyperskill.azurecr.io/hyperstyle:${{ github.sha }}
+      credentials:
+        username: ${{ secrets.REGISTRY_USER }}
+        password: ${{ secrets.REGISTRY_PASSWORD }}
+    steps:
+      - name: Lint
+        run: |
+          cd /review
+          /hyperstyle/bin/mypy .
+
   build:
     runs-on: [ self-hosted, small ]
     needs:
diff --git a/hyperstyle/src/python/common/tool_arguments.py b/hyperstyle/src/python/common/tool_arguments.py
index d4376cc0..785671d9 100644
--- a/hyperstyle/src/python/common/tool_arguments.py
+++ b/hyperstyle/src/python/common/tool_arguments.py
@@ -2,7 +2,6 @@
 
 from dataclasses import dataclass
 from enum import Enum, unique
-from typing import ClassVar
 
 from hyperstyle.src.python.review.common.language import Language
 from hyperstyle.src.python.review.common.language_version import LanguageVersion
@@ -30,6 +29,10 @@ class ArgumentsInfo:
     description: str
 
 
+INSPECTORS = [inspector.lower() for inspector in InspectorType.available_values()]
+DISABLED_INSPECTORS_EXAMPLE = f"-d {INSPECTORS[0].lower()},{INSPECTORS[1].lower()}"
+
+
 @unique
 class RunToolArgument(Enum):
     VERBOSITY = ArgumentsInfo(
@@ -43,15 +46,12 @@ class RunToolArgument(Enum):
         "default is 0",
     )
 
-    inspectors: ClassVar = [inspector.lower() for inspector in InspectorType.available_values()]
-    disabled_inspectors_example = f"-d {inspectors[0].lower()},{inspectors[1].lower()}"
-
     DISABLE = ArgumentsInfo(
         "-d",
         "--disable",
         'Disable inspectors. '
-        f'Available values: {", ".join(inspectors)}. '
-        f'Example: {disabled_inspectors_example}',
+        f'Available values: {", ".join(INSPECTORS)}. '
+        f'Example: {DISABLED_INSPECTORS_EXAMPLE}',
     )
 
     DUPLICATES = ArgumentsInfo(
diff --git a/hyperstyle/src/python/review/application_config.py b/hyperstyle/src/python/review/application_config.py
index dc177612..56ee6daa 100644
--- a/hyperstyle/src/python/review/application_config.py
+++ b/hyperstyle/src/python/review/application_config.py
@@ -13,7 +13,7 @@ class ApplicationConfig:
     disabled_inspectors: set[InspectorType]
     allow_duplicates: bool
     n_cpu: int
-    inspectors_config: dict
+    inspectors_config: dict[str, object]
     with_all_categories: bool
     start_line: int = 1
     language: Language | None = None
diff --git a/hyperstyle/src/python/review/common/file_system.py b/hyperstyle/src/python/review/common/file_system.py
index aa39cc5c..7d785769 100644
--- a/hyperstyle/src/python/review/common/file_system.py
+++ b/hyperstyle/src/python/review/common/file_system.py
@@ -88,10 +88,6 @@ def new_temp_dir() -> Iterator[Path]:
         yield Path(temp_dir)
 
 
-def new_temp_file(suffix: Extension = Extension.EMPTY) -> Iterator[tuple[str, str]]:
-    yield tempfile.mkstemp(suffix=suffix.value)
-
-
 def get_file_line(path: Path, line_number: int) -> str:
     return linecache.getline(
         str(path),
diff --git a/hyperstyle/src/python/review/common/parallel_runner.py b/hyperstyle/src/python/review/common/parallel_runner.py
index c2013fc0..b6380b37 100644
--- a/hyperstyle/src/python/review/common/parallel_runner.py
+++ b/hyperstyle/src/python/review/common/parallel_runner.py
@@ -56,9 +56,11 @@ def inspect_in_parallel(
         return issues
 
     with multiprocessing.Pool(config.n_cpu) as pool:
-        issues = pool.map(
-            functools.partial(inspector_runner, data, config),
-            inspectors_to_run,
+        return list(
+            itertools.chain(
+                *pool.map(
+                    functools.partial(inspector_runner, data, config),
+                    inspectors_to_run,
+                )
+            )
         )
-
-    return list(itertools.chain(*issues))
diff --git a/hyperstyle/src/python/review/inspectors/common/inspector/base_inspector.py b/hyperstyle/src/python/review/inspectors/common/inspector/base_inspector.py
index 8ad519cc..12bc8122 100644
--- a/hyperstyle/src/python/review/inspectors/common/inspector/base_inspector.py
+++ b/hyperstyle/src/python/review/inspectors/common/inspector/base_inspector.py
@@ -138,10 +138,6 @@ def convert_to_base_issues(
         return base_issues
 
     def _get_inspection_result(self, code_text: str, file_path: Path) -> list[BaseIssue]:
-        if self.host is None or self.port is None:
-            msg = "Connection parameters is not set up."
-            raise Exception(msg)
-
         client = IJClient(self.host, self.port)
 
         code = model_pb2.Code()
diff --git a/hyperstyle/src/python/review/inspectors/common/inspector/ij_client.py b/hyperstyle/src/python/review/inspectors/common/inspector/ij_client.py
index f06e42c8..4c651609 100644
--- a/hyperstyle/src/python/review/inspectors/common/inspector/ij_client.py
+++ b/hyperstyle/src/python/review/inspectors/common/inspector/ij_client.py
@@ -8,6 +8,8 @@
 
 
 class IJClient:
+    stub: model_pb2_grpc.CodeInspectionServiceStub
+
     def __init__(self, host: str = "localhost", port: int = 8080) -> None:
         self.host = host
         self.port = port
@@ -22,10 +24,10 @@ def __init__(self, host: str = "localhost", port: int = 8080) -> None:
             msg = "Failed to connect to ij code server"
             raise Exception(msg) from e
         else:
-            self.stub = model_pb2_grpc.CodeInspectionServiceStub(self.channel)
+            self.stub = model_pb2_grpc.CodeInspectionServiceStub(self.channel)  # type: ignore[no-untyped-call]
 
     def inspect(self, code: model_pb2.Code) -> model_pb2.InspectionResult:
         return self.stub.inspect(code, timeout=TIMEOUT)
 
     def init(self, service: model_pb2.Service) -> model_pb2.InitResult:
-        return self.stub.init(service, timeout=TIMEOUT)
+        return self.stub.init(service, timeout=TIMEOUT)  # type: ignore[attr-defined]
diff --git a/hyperstyle/src/python/review/inspectors/common/issue/base_issue_converter.py b/hyperstyle/src/python/review/inspectors/common/issue/base_issue_converter.py
index ca3ce617..5739a91c 100644
--- a/hyperstyle/src/python/review/inspectors/common/issue/base_issue_converter.py
+++ b/hyperstyle/src/python/review/inspectors/common/issue/base_issue_converter.py
@@ -8,7 +8,7 @@
     get_issue_class_by_issue_type,
     get_measure_name_by_measurable_issue_type,
     IssueData,
-    Measurable,
+    MeasurableIssue,
 )
 
 if TYPE_CHECKING:
@@ -36,7 +36,7 @@ def convert_base_issue(base_issue: BaseIssue, issue_configs_handler: IssueConfig
     issue_data[IssueData.DESCRIPTION.value] = issue_configs_handler.get_description(origin_class, description)
 
     issue_class = get_issue_class_by_issue_type(issue_type)
-    if issubclass(issue_class, Measurable):
+    if issubclass(issue_class, MeasurableIssue):
         measure = issue_configs_handler.parse_measure(origin_class, description)
         if measure is None:
             logger.error(f"{inspector_type.value}: Unable to parse measure.")
diff --git a/hyperstyle/src/python/review/inspectors/common/issue/issue.py b/hyperstyle/src/python/review/inspectors/common/issue/issue.py
index 8de9d492..7bfe76f1 100644
--- a/hyperstyle/src/python/review/inspectors/common/issue/issue.py
+++ b/hyperstyle/src/python/review/inspectors/common/issue/issue.py
@@ -1,11 +1,10 @@
 from __future__ import annotations
 
-import abc
 import logging
 from collections import defaultdict
 from dataclasses import dataclass
 from enum import Enum, unique
-from typing import Any, TYPE_CHECKING
+from typing import Any, Protocol, runtime_checkable, TYPE_CHECKING
 
 if TYPE_CHECKING:
     from pathlib import Path
@@ -206,10 +205,9 @@ class BaseIssue(ShortIssue):
     difficulty: IssueDifficulty
 
 
-class Measurable(abc.ABC):
-    @abc.abstractmethod
-    def measure(self) -> int:
-        pass
+@runtime_checkable
+class MeasurableIssue(Protocol):
+    def measure(self) -> int: ...
 
 
 @dataclass(frozen=True)
@@ -218,7 +216,7 @@ class CodeIssue(BaseIssue):
 
 
 @dataclass(frozen=True)
-class BoolExprLenIssue(BaseIssue, Measurable):
+class BoolExprLenIssue(BaseIssue, MeasurableIssue):
     bool_expr_len: int
     type = IssueType.BOOL_EXPR_LEN
 
@@ -227,7 +225,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class FuncLenIssue(BaseIssue, Measurable):
+class FuncLenIssue(BaseIssue, MeasurableIssue):
     func_len: int
     type = IssueType.FUNC_LEN
 
@@ -236,7 +234,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class LineLenIssue(BaseIssue, Measurable):
+class LineLenIssue(BaseIssue, MeasurableIssue):
     line_len: int
     type = IssueType.LINE_LEN
 
@@ -245,7 +243,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class CyclomaticComplexityIssue(BaseIssue, Measurable):
+class CyclomaticComplexityIssue(BaseIssue, MeasurableIssue):
     cc_value: int
     type = IssueType.CYCLOMATIC_COMPLEXITY
 
@@ -254,7 +252,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class InheritanceIssue(BaseIssue, Measurable):
+class InheritanceIssue(BaseIssue, MeasurableIssue):
     inheritance_tree_depth: int
     type = IssueType.INHERITANCE_DEPTH
 
@@ -263,7 +261,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class ChildrenNumberIssue(BaseIssue, Measurable):
+class ChildrenNumberIssue(BaseIssue, MeasurableIssue):
     children_number: int
     type = IssueType.CHILDREN_NUMBER
 
@@ -272,7 +270,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class WeightedMethodIssue(BaseIssue, Measurable):
+class WeightedMethodIssue(BaseIssue, MeasurableIssue):
     weighted_method: int
     type = IssueType.WEIGHTED_METHOD
 
@@ -281,7 +279,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class CouplingIssue(BaseIssue, Measurable):
+class CouplingIssue(BaseIssue, MeasurableIssue):
     class_objects_coupling: int
     type = IssueType.COUPLING
 
@@ -290,7 +288,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class CohesionIssue(BaseIssue, Measurable):
+class CohesionIssue(BaseIssue, MeasurableIssue):
     cohesion_lack: int
     type = IssueType.COHESION
 
@@ -299,7 +297,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class ClassResponseIssue(BaseIssue, Measurable):
+class ClassResponseIssue(BaseIssue, MeasurableIssue):
     class_response: int
     type = IssueType.CLASS_RESPONSE
 
@@ -308,7 +306,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class MethodNumberIssue(BaseIssue, Measurable):
+class MethodNumberIssue(BaseIssue, MeasurableIssue):
     method_number: int
     type = IssueType.METHOD_NUMBER
 
@@ -317,7 +315,7 @@ def measure(self) -> int:
 
 
 @dataclass(frozen=True)
-class MaintainabilityLackIssue(BaseIssue, Measurable):
+class MaintainabilityLackIssue(BaseIssue, MeasurableIssue):
     maintainability_lack: int
     type = IssueType.MAINTAINABILITY
 
diff --git a/hyperstyle/src/python/review/inspectors/common/issue/issue_configs.py b/hyperstyle/src/python/review/inspectors/common/issue/issue_configs.py
index 431909cd..d5c7866e 100644
--- a/hyperstyle/src/python/review/inspectors/common/issue/issue_configs.py
+++ b/hyperstyle/src/python/review/inspectors/common/issue/issue_configs.py
@@ -2,7 +2,7 @@
 
 import logging
 from dataclasses import dataclass, field
-from typing import Optional, TYPE_CHECKING
+from typing import TYPE_CHECKING
 
 from hyperstyle.src.python.review.inspectors.common.utils import (
     contains_format_fields,
@@ -136,7 +136,7 @@ def __init__(self, *issue_configs: IssueConfig) -> None:
             issue_config.origin_class: issue_config for issue_config in issue_configs
         }
 
-    def _parse_description(self, origin_class: str, description: str) -> tuple | None:
+    def _parse_description(self, origin_class: str, description: str) -> tuple[object, ...] | None:
         """Parse a description.
 
         :param origin_class: An origin class of issue.
@@ -158,7 +158,7 @@ def _parse_description(self, origin_class: str, description: str) -> tuple | Non
 
         return args
 
-    def parse_measure(self, origin_class: str, description: str) -> Optional:
+    def parse_measure(self, origin_class: str, description: str) -> object | None:
         """Parse a measure from a description.
 
         :param origin_class: An origin class of issue.
diff --git a/hyperstyle/src/python/review/inspectors/common/xml_parser.py b/hyperstyle/src/python/review/inspectors/common/xml_parser.py
index 0ab99557..bf4c68d4 100644
--- a/hyperstyle/src/python/review/inspectors/common/xml_parser.py
+++ b/hyperstyle/src/python/review/inspectors/common/xml_parser.py
@@ -20,12 +20,12 @@
 logger = logging.getLogger(__name__)
 
 
-def __should_handle_element(element: ET) -> bool:
+def __should_handle_element(element: Element) -> bool:
     """Checks if a tree element is a file."""
     return element.tag == "file"
 
 
-def __is_error(element: ET) -> bool:
+def __is_error(element: Element) -> bool:
     """Checks if a tree element is an error."""
     return element.tag == "error"
 
diff --git a/hyperstyle/src/python/review/inspectors/flake8/flake8.py b/hyperstyle/src/python/review/inspectors/flake8/flake8.py
index ca71bb20..d06a7d92 100644
--- a/hyperstyle/src/python/review/inspectors/flake8/flake8.py
+++ b/hyperstyle/src/python/review/inspectors/flake8/flake8.py
@@ -91,6 +91,7 @@ def choose_issue_type(code: str) -> IssueType:
             return CODE_TO_ISSUE_TYPE[code]
 
         regex_match = re.match(r"^([A-Z]+)(\d)\d*$", code, re.IGNORECASE)
+        assert regex_match is not None, f"flake8: {code} - unexpected error code format"
         code_prefix = regex_match.group(1)
         first_code_number = regex_match.group(2)
 
diff --git a/hyperstyle/src/python/review/inspectors/ij_java/ij_java.py b/hyperstyle/src/python/review/inspectors/ij_java/ij_java.py
index 5b3c43aa..d72ebe28 100644
--- a/hyperstyle/src/python/review/inspectors/ij_java/ij_java.py
+++ b/hyperstyle/src/python/review/inspectors/ij_java/ij_java.py
@@ -12,7 +12,7 @@
 
 class JavaIJInspector(BaseIJInspector):
     inspector_type = InspectorType.IJ_JAVA
-    language_id = model_pb2.LanguageId.Java
+    language_id = model_pb2.LanguageId.Java  # type: ignore[attr-defined]
     issue_configs = ISSUE_CONFIGS
     ij_inspection_to_issue_type = IJ_INSPECTION_TO_ISSUE_TYPE
     ij_message_to_issue_type = IJ_MESSAGE_TO_ISSUE_TYPE
diff --git a/hyperstyle/src/python/review/inspectors/ij_java/issue_types.py b/hyperstyle/src/python/review/inspectors/ij_java/issue_types.py
index 5c0fe456..17f7a93b 100644
--- a/hyperstyle/src/python/review/inspectors/ij_java/issue_types.py
+++ b/hyperstyle/src/python/review/inspectors/ij_java/issue_types.py
@@ -1,5 +1,10 @@
 from __future__ import annotations
 
-IJ_INSPECTION_TO_ISSUE_TYPE = {}
+from typing import TYPE_CHECKING
 
-IJ_MESSAGE_TO_ISSUE_TYPE = {}
+if TYPE_CHECKING:
+    from hyperstyle.src.python.review.inspectors.common.issue.issue import IssueType
+
+IJ_INSPECTION_TO_ISSUE_TYPE: dict[str, IssueType] = {}
+
+IJ_MESSAGE_TO_ISSUE_TYPE: dict[str, dict[str, IssueType]] = {}
diff --git a/hyperstyle/src/python/review/inspectors/ij_kotlin/ij_kotlin.py b/hyperstyle/src/python/review/inspectors/ij_kotlin/ij_kotlin.py
index bc78323d..bbf661b7 100644
--- a/hyperstyle/src/python/review/inspectors/ij_kotlin/ij_kotlin.py
+++ b/hyperstyle/src/python/review/inspectors/ij_kotlin/ij_kotlin.py
@@ -12,7 +12,7 @@
 
 class KotlinIJInspector(BaseIJInspector):
     inspector_type = InspectorType.IJ_KOTLIN
-    language_id = model_pb2.LanguageId.kotlin
+    language_id = model_pb2.LanguageId.kotlin  # type: ignore[attr-defined]
     issue_configs = ISSUE_CONFIGS
     ij_inspection_to_issue_type = IJ_INSPECTION_TO_ISSUE_TYPE
     ij_message_to_issue_type = IJ_MESSAGE_TO_ISSUE_TYPE
diff --git a/hyperstyle/src/python/review/inspectors/ij_kotlin/issue_types.py b/hyperstyle/src/python/review/inspectors/ij_kotlin/issue_types.py
index 5c0fe456..17f7a93b 100644
--- a/hyperstyle/src/python/review/inspectors/ij_kotlin/issue_types.py
+++ b/hyperstyle/src/python/review/inspectors/ij_kotlin/issue_types.py
@@ -1,5 +1,10 @@
 from __future__ import annotations
 
-IJ_INSPECTION_TO_ISSUE_TYPE = {}
+from typing import TYPE_CHECKING
 
-IJ_MESSAGE_TO_ISSUE_TYPE = {}
+if TYPE_CHECKING:
+    from hyperstyle.src.python.review.inspectors.common.issue.issue import IssueType
+
+IJ_INSPECTION_TO_ISSUE_TYPE: dict[str, IssueType] = {}
+
+IJ_MESSAGE_TO_ISSUE_TYPE: dict[str, dict[str, IssueType]] = {}
diff --git a/hyperstyle/src/python/review/inspectors/ij_python/ij_python.py b/hyperstyle/src/python/review/inspectors/ij_python/ij_python.py
index 10016dab..3e864fa0 100644
--- a/hyperstyle/src/python/review/inspectors/ij_python/ij_python.py
+++ b/hyperstyle/src/python/review/inspectors/ij_python/ij_python.py
@@ -12,7 +12,7 @@
 
 class PythonIJInspector(BaseIJInspector):
     inspector_type = InspectorType.IJ_PYTHON
-    language_id = model_pb2.LanguageId.Python
+    language_id = model_pb2.LanguageId.Python  # type: ignore[attr-defined]
     issue_configs = ISSUE_CONFIGS
     ij_inspection_to_issue_type = IJ_INSPECTION_TO_ISSUE_TYPE
     ij_message_to_issue_type = IJ_MESSAGE_TO_ISSUE_TYPE
diff --git a/hyperstyle/src/python/review/inspectors/ij_python/issue_types.py b/hyperstyle/src/python/review/inspectors/ij_python/issue_types.py
index aa715272..6f14d8ae 100644
--- a/hyperstyle/src/python/review/inspectors/ij_python/issue_types.py
+++ b/hyperstyle/src/python/review/inspectors/ij_python/issue_types.py
@@ -3,7 +3,7 @@
 from hyperstyle.src.python.review.inspectors.common.issue.issue import IssueType
 
 # Synchronized with https://github.com/JetBrains-Research/code-quality-ij-server/tree/master/docs/inspections/python
-IJ_INSPECTION_TO_ISSUE_TYPE = {
+IJ_INSPECTION_TO_ISSUE_TYPE: dict[str, IssueType] = {
     # BEST_PRACTICES
     "PyUnusedLocalInspection": IssueType.BEST_PRACTICES,
     "PySimplifyBooleanCheckInspection": IssueType.BEST_PRACTICES,
@@ -63,7 +63,7 @@
     "PyUnresolvedReferencesInspection": IssueType.ERROR_PRONE,
 }
 
-IJ_MESSAGE_TO_ISSUE_TYPE = {
+IJ_MESSAGE_TO_ISSUE_TYPE: dict[str, dict[str, IssueType]] = {
     "PyDataclassInspection": {
         "is useless until " "__post_init__" " is declared": IssueType.BEST_PRACTICES,
         "should take all init-only variables (incl. inherited) in the same order as they are defined": IssueType.BEST_PRACTICES,
diff --git a/hyperstyle/src/python/review/inspectors/pyast/python_ast.py b/hyperstyle/src/python/review/inspectors/pyast/python_ast.py
index a7ebd6ab..aa61d5e0 100644
--- a/hyperstyle/src/python/review/inspectors/pyast/python_ast.py
+++ b/hyperstyle/src/python/review/inspectors/pyast/python_ast.py
@@ -145,7 +145,7 @@ def inspect(cls, path: Path, config: dict[str, Any]) -> list[BaseIssue]:
 
         path_to_files = language.filter_paths_by_language(path_to_files, Language.PYTHON)
 
-        metrics = []
+        metrics: list[BaseIssue] = []
         for path_to_file in path_to_files:
             file_content = path_to_file.read_text()
             tree = ast.parse(file_content, path_to_file.name)
diff --git a/hyperstyle/src/python/review/inspectors/pylint/pylint.py b/hyperstyle/src/python/review/inspectors/pylint/pylint.py
index f94c18dc..149981b9 100644
--- a/hyperstyle/src/python/review/inspectors/pylint/pylint.py
+++ b/hyperstyle/src/python/review/inspectors/pylint/pylint.py
@@ -64,7 +64,7 @@ def parse(cls, output: str) -> list[BaseIssue]:
         row_re = re.compile(r"^(.*):(\d+):(\d+):([IRCWEF]\d+):(.*)$", re.MULTILINE)
         issue_configs_handler = IssueConfigsHandler(*ISSUE_CONFIGS)
 
-        issues = []
+        issues: list[BaseIssue] = []
         for groups in row_re.findall(output):
             if groups[1] == INFO_CATEGORY:
                 continue
@@ -76,7 +76,7 @@ def parse(cls, output: str) -> list[BaseIssue]:
             origin_class = groups[3]
             issue_type = cls.choose_issue_type(origin_class)
             if issue_type not in cls.supported_issue_types:
-                logger.error("pylint: unsupported issue type %s", issue_type.__name__)
+                logger.error("pylint: unsupported issue type %s", issue_type.__name__)  # type: ignore[attr-defined]
                 continue
 
             base_issue = BaseIssue(
diff --git a/hyperstyle/src/python/review/inspectors/radon/radon.py b/hyperstyle/src/python/review/inspectors/radon/radon.py
index dd6ea992..1bff57bb 100644
--- a/hyperstyle/src/python/review/inspectors/radon/radon.py
+++ b/hyperstyle/src/python/review/inspectors/radon/radon.py
@@ -31,7 +31,7 @@ def inspect_in_memory(cls, code: str, config: dict[str, Any]) -> list[BaseIssue]
 
     @classmethod
     def inspect(cls, path: Path, config: dict[str, Any]) -> list[BaseIssue]:
-        mi_command = [
+        mi_command: list[str] = [
             sys.executable,
             "-m",
             "radon",
@@ -39,7 +39,7 @@ def inspect(cls, path: Path, config: dict[str, Any]) -> list[BaseIssue]:
             "--max",
             "F",  # set the maximum MI rank to display
             "--show",  # actual MI value is shown in results, alongside the rank
-            path,
+            str(path),
         ]
 
         mi_output = run_in_subprocess(mi_command)
diff --git a/hyperstyle/src/python/review/logging_config.py b/hyperstyle/src/python/review/logging_config.py
index ab7ef702..ff50d915 100644
--- a/hyperstyle/src/python/review/logging_config.py
+++ b/hyperstyle/src/python/review/logging_config.py
@@ -1,8 +1,12 @@
 from __future__ import annotations
 
 import sys
+from typing import TYPE_CHECKING
 
-logging_config: dict[str, object] = {
+if TYPE_CHECKING:
+    from logging.config import _DictConfigArgs
+
+logging_config: _DictConfigArgs = {
     "version": 1,
     "formatters": {
         "common": {
diff --git a/hyperstyle/src/python/review/quality/model.py b/hyperstyle/src/python/review/quality/model.py
index cb72606d..f178146e 100644
--- a/hyperstyle/src/python/review/quality/model.py
+++ b/hyperstyle/src/python/review/quality/model.py
@@ -34,7 +34,7 @@ def __le__(self, other: QualityType) -> bool:
 
 class Rule(abc.ABC):
     rule_type: IssueType
-    quality_type: QualityType
+    quality_type: QualityType | None
     next_level_type: QualityType
     next_level_delta: float
     value: int
@@ -43,6 +43,10 @@ class Rule(abc.ABC):
     def apply(self, *args, **kwargs) -> None:
         pass
 
+    @abc.abstractmethod
+    def merge(self, other: Rule) -> Rule:
+        raise NotImplementedError
+
 
 class Quality:
     def __init__(self, rules: list[Rule]) -> None:
@@ -50,7 +54,10 @@ def __init__(self, rules: list[Rule]) -> None:
 
     @property
     def quality_type(self) -> QualityType:
-        return min((rule.quality_type for rule in self.rules), default=QualityType.EXCELLENT)
+        return min(
+            (rule.quality_type for rule in self.rules if rule.quality_type is not None),
+            default=QualityType.EXCELLENT,
+        )
 
     @property
     def next_quality_type(self) -> QualityType:
diff --git a/hyperstyle/src/python/review/quality/penalty.py b/hyperstyle/src/python/review/quality/penalty.py
index 300a1e28..6ed1b675 100644
--- a/hyperstyle/src/python/review/quality/penalty.py
+++ b/hyperstyle/src/python/review/quality/penalty.py
@@ -59,7 +59,7 @@ class PenaltyConfig:
 class PreviousIssue:
     origin_class: str
     number: int
-    category: IssueType = None
+    category: IssueType | None = None
 
 
 def get_previous_issues_by_language(lang_to_history: str | None, language: Language) -> list[PreviousIssue]:
@@ -78,12 +78,10 @@ def get_previous_issues_by_language(lang_to_history: str | None, language: Langu
 
 def categorize(previous_issues: list[PreviousIssue], current_issues: list[BaseIssue]) -> None:
     """For each previously made issue determines its category, with the help of current issues."""
-    origin_class_to_category = {}
-    for issue in current_issues:
-        origin_class_to_category[issue.origin_class] = issue.type
+    origin_class_to_category = {issue.origin_class: issue.type for issue in current_issues}
 
     for issue in previous_issues:
-        issue.category = origin_class_to_category.get(issue.origin_class, None)
+        issue.category = origin_class_to_category.get(issue.origin_class)
 
 
 class Punisher:
@@ -154,9 +152,13 @@ def _get_penalty_coefficient(
             filter(lambda issue: issue.origin_class in penalizing_classes, previous_issues)
         )
 
-        coefficient = 0
+        coefficient: float = 0
         for issue in penalizing_issues:
-            coefficient += ISSUE_TYPE_TO_PENALTY_COEFFICIENT.get(issue.category, 1) * issue.number
+            coefficient += (
+                ISSUE_TYPE_TO_PENALTY_COEFFICIENT.get(issue.category, 1) * issue.number
+                if issue.category
+                else issue.number
+            )
 
         return coefficient
 
@@ -164,7 +166,7 @@ def _get_normalized_penalty_coefficient(self, current_issues: list[BaseIssue]) -
         """The penalty coefficient is normalized by the formula: k / (k + n),
         where k is the penalty coefficient, n is the number of current issues.
         """
-        coefficient = 0
+        coefficient: float = 0
         if current_issues:
             coefficient = self._penalty_coefficient / (self._penalty_coefficient + len(current_issues))
 
@@ -185,7 +187,11 @@ def _get_issue_class_to_influence(
 
         result = {}
         for issue in penalizing_issues:
-            issue_coefficient = ISSUE_TYPE_TO_PENALTY_COEFFICIENT.get(issue.category, 1) * issue.number
+            issue_coefficient = (
+                ISSUE_TYPE_TO_PENALTY_COEFFICIENT.get(issue.category, 1) * issue.number
+                if issue.category
+                else issue.number
+            )
             normalized_issue_coefficient = issue_coefficient / (
                 self._penalty_coefficient + len(current_issues)
             )
diff --git a/hyperstyle/src/python/review/quality/rules/best_practices_scoring.py b/hyperstyle/src/python/review/quality/rules/best_practices_scoring.py
index 9d5e4ab5..5ba01148 100644
--- a/hyperstyle/src/python/review/quality/rules/best_practices_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/best_practices_scoring.py
@@ -57,13 +57,16 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: BestPracticesRule) -> BestPracticesRule:
+    def merge(self, other: Rule) -> BestPracticesRule:
+        assert isinstance(other, BestPracticesRule)
         config = BestPracticesRuleConfig(
             min(self.config.n_best_practices_moderate, other.config.n_best_practices_moderate),
             min(self.config.n_best_practices_good, other.config.n_best_practices_good),
             n_files=self.config.n_files + other.config.n_files,
         )
         result_rule = BestPracticesRule(config)
+        assert self.n_best_practices is not None
+        assert other.n_best_practices is not None
         result_rule.apply(self.n_best_practices + other.n_best_practices)
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/boolean_length_scoring.py b/hyperstyle/src/python/review/quality/rules/boolean_length_scoring.py
index 6c2bc8b4..74b56c2e 100644
--- a/hyperstyle/src/python/review/quality/rules/boolean_length_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/boolean_length_scoring.py
@@ -64,13 +64,16 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: BooleanExpressionRule) -> BooleanExpressionRule:
+    def merge(self, other: Rule) -> BooleanExpressionRule:
+        assert isinstance(other, BooleanExpressionRule)
         config = BooleanExpressionRuleConfig(
             min(self.config.bool_expr_len_bad, other.config.bool_expr_len_bad),
             min(self.config.bool_expr_len_moderate, other.config.bool_expr_len_moderate),
             min(self.config.bool_expr_len_good, other.config.bool_expr_len_good),
         )
         result_rule = BooleanExpressionRule(config)
+        assert self.bool_expr_len is not None
+        assert other.bool_expr_len is not None
         result_rule.apply(max(self.bool_expr_len, other.bool_expr_len))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/class_response_scoring.py b/hyperstyle/src/python/review/quality/rules/class_response_scoring.py
index 6eeefcc4..a57dcf93 100644
--- a/hyperstyle/src/python/review/quality/rules/class_response_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/class_response_scoring.py
@@ -51,12 +51,15 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: ResponseRule) -> ResponseRule:
+    def merge(self, other: Rule) -> ResponseRule:
+        assert isinstance(other, ResponseRule)
         config = ResponseRuleConfig(
             min(self.config.response_moderate, other.config.response_moderate),
             min(self.config.response_good, other.config.response_good),
         )
         result_rule = ResponseRule(config)
+        assert self.response is not None
+        assert other.response is not None
         result_rule.apply(max(self.response, other.response))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/code_style_scoring.py b/hyperstyle/src/python/review/quality/rules/code_style_scoring.py
index 94837c35..038b27f1 100644
--- a/hyperstyle/src/python/review/quality/rules/code_style_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/code_style_scoring.py
@@ -72,8 +72,8 @@ def __init__(self, config: CodeStyleRuleConfig) -> None:
         self.rule_type = IssueType.CODE_STYLE
         self.total_lines = 0
         self.n_code_style_lines = 0
-        self.ratio = 0
-        self.quality_type = None
+        self.ratio: float = 0
+        self.quality_type: QualityType | None = None
         self.next_level_delta = 0
 
     # TODO: refactor
@@ -119,7 +119,10 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: CodeStyleRule) -> CodeStyleRule:
+    def merge(self, other: Rule) -> CodeStyleRule:
+        assert isinstance(other, CodeStyleRule)
+        assert self.quality_type is not None
+        assert other.quality_type is not None
         if self.quality_type > other.quality_type:
             return other
         return self
diff --git a/hyperstyle/src/python/review/quality/rules/cohesion_scoring.py b/hyperstyle/src/python/review/quality/rules/cohesion_scoring.py
index 79c20423..064d2420 100644
--- a/hyperstyle/src/python/review/quality/rules/cohesion_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/cohesion_scoring.py
@@ -61,13 +61,16 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: CohesionRule) -> CohesionRule:
+    def merge(self, other: Rule) -> CohesionRule:
+        assert isinstance(other, CohesionRule)
         config = CohesionRuleConfig(
             min(self.config.cohesion_lack_bad, other.config.cohesion_lack_bad),
             min(self.config.cohesion_lack_moderate, other.config.cohesion_lack_moderate),
             min(self.config.cohesion_lack_good, other.config.cohesion_lack_good),
         )
         result_rule = CohesionRule(config)
+        assert self.cohesion_lack is not None
+        assert other.cohesion_lack is not None
         result_rule.apply(max(self.cohesion_lack, other.cohesion_lack))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/complexity_scoring.py b/hyperstyle/src/python/review/quality/rules/complexity_scoring.py
index f9685fb7..20da2e87 100644
--- a/hyperstyle/src/python/review/quality/rules/complexity_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/complexity_scoring.py
@@ -58,13 +58,16 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: ComplexityRule) -> ComplexityRule:
+    def merge(self, other: Rule) -> ComplexityRule:
+        assert isinstance(other, ComplexityRule)
         config = ComplexityRuleConfig(
             min(self.config.complexity_bad, other.config.complexity_bad),
             min(self.config.complexity_moderate, other.config.complexity_moderate),
             min(self.config.complexity_good, other.config.complexity_good),
         )
         result_rule = ComplexityRule(config)
+        assert self.complexity is not None
+        assert other.complexity is not None
         result_rule.apply(max(self.complexity, other.complexity))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/coupling_scoring.py b/hyperstyle/src/python/review/quality/rules/coupling_scoring.py
index 85831061..f778929b 100644
--- a/hyperstyle/src/python/review/quality/rules/coupling_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/coupling_scoring.py
@@ -51,12 +51,15 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.MODERATE
         return QualityType.EXCELLENT
 
-    def merge(self, other: CouplingRule) -> CouplingRule:
+    def merge(self, other: Rule) -> CouplingRule:
+        assert isinstance(other, CouplingRule)
         config = CouplingRuleConfig(
             min(self.config.coupling_bad, other.config.coupling_bad),
             min(self.config.coupling_moderate, other.config.coupling_moderate),
         )
         result_rule = CouplingRule(config)
+        assert self.coupling is not None
+        assert other.coupling is not None
         result_rule.apply(max(self.coupling, other.coupling))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/cyclomatic_complexity_scoring.py b/hyperstyle/src/python/review/quality/rules/cyclomatic_complexity_scoring.py
index 73859e1e..c90c95e2 100644
--- a/hyperstyle/src/python/review/quality/rules/cyclomatic_complexity_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/cyclomatic_complexity_scoring.py
@@ -62,12 +62,15 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.MODERATE
         return QualityType.EXCELLENT
 
-    def merge(self, other: CyclomaticComplexityRule) -> CyclomaticComplexityRule:
+    def merge(self, other: Rule) -> CyclomaticComplexityRule:
+        assert isinstance(other, CyclomaticComplexityRule)
         config = CyclomaticComplexityRuleConfig(
             min(self.config.cc_value_bad, other.config.cc_value_bad),
             min(self.config.cc_value_moderate, other.config.cc_value_moderate),
         )
         result_rule = CyclomaticComplexityRule(config)
+        assert self.cc_value is not None
+        assert other.cc_value is not None
         result_rule.apply(max(self.cc_value, other.cc_value))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/error_prone_scoring.py b/hyperstyle/src/python/review/quality/rules/error_prone_scoring.py
index 8879906e..a5227292 100644
--- a/hyperstyle/src/python/review/quality/rules/error_prone_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/error_prone_scoring.py
@@ -48,9 +48,12 @@ def apply(self, n_error_prone: int) -> None:
     def __get_next_quality_type(self) -> QualityType:
         return QualityType.EXCELLENT
 
-    def merge(self, other: ErrorProneRule) -> ErrorProneRule:
+    def merge(self, other: Rule) -> ErrorProneRule:
+        assert isinstance(other, ErrorProneRule)
         config = ErrorProneRuleConfig(min(self.config.n_error_prone_bad, other.config.n_error_prone_bad))
         result_rule = ErrorProneRule(config)
+        assert self.n_error_prone is not None
+        assert other.n_error_prone is not None
         result_rule.apply(self.n_error_prone + other.n_error_prone)
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/function_length_scoring.py b/hyperstyle/src/python/review/quality/rules/function_length_scoring.py
index 14be729f..c1449986 100644
--- a/hyperstyle/src/python/review/quality/rules/function_length_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/function_length_scoring.py
@@ -51,11 +51,14 @@ def apply(self, func_len: int) -> None:
     def __get_next_quality_type(self) -> QualityType:
         return QualityType.EXCELLENT
 
-    def merge(self, other: FunctionLengthRule) -> FunctionLengthRule:
+    def merge(self, other: Rule) -> FunctionLengthRule:
+        assert isinstance(other, FunctionLengthRule)
         config = FunctionLengthRuleConfig(
             min(self.config.func_len_bad, other.config.func_len_bad),
         )
         result_rule = FunctionLengthRule(config)
+        assert self.func_len is not None
+        assert other.func_len is not None
         result_rule.apply(max(self.func_len, other.func_len))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/inheritance_depth_scoring.py b/hyperstyle/src/python/review/quality/rules/inheritance_depth_scoring.py
index 79a87a74..6e0191a9 100644
--- a/hyperstyle/src/python/review/quality/rules/inheritance_depth_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/inheritance_depth_scoring.py
@@ -44,9 +44,12 @@ def apply(self, depth: int) -> None:
     def __get_next_quality_type(self) -> QualityType:
         return QualityType.EXCELLENT
 
-    def merge(self, other: InheritanceDepthRule) -> InheritanceDepthRule:
+    def merge(self, other: Rule) -> InheritanceDepthRule:
+        assert isinstance(other, InheritanceDepthRule)
         config = InheritanceDepthRuleConfig(min(self.config.depth_bad, other.config.depth_bad))
         result_rule = InheritanceDepthRule(config)
+        assert self.depth is not None
+        assert other.depth is not None
         result_rule.apply(max(self.depth, other.depth))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/line_len_scoring.py b/hyperstyle/src/python/review/quality/rules/line_len_scoring.py
index 0c0d290b..4db860e0 100644
--- a/hyperstyle/src/python/review/quality/rules/line_len_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/line_len_scoring.py
@@ -59,7 +59,8 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: LineLengthRule) -> LineLengthRule:
+    def merge(self, other: Rule) -> LineLengthRule:
+        assert isinstance(other, LineLengthRule)
         config = LineLengthRuleConfig(
             min(self.config.n_line_len_bad, other.config.n_line_len_bad),
             min(self.config.n_line_len_moderate, other.config.n_line_len_moderate),
diff --git a/hyperstyle/src/python/review/quality/rules/maintainability_scoring.py b/hyperstyle/src/python/review/quality/rules/maintainability_scoring.py
index b08860c0..bec14770 100644
--- a/hyperstyle/src/python/review/quality/rules/maintainability_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/maintainability_scoring.py
@@ -75,13 +75,16 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: MaintainabilityRule) -> MaintainabilityRule:
+    def merge(self, other: Rule) -> MaintainabilityRule:
+        assert isinstance(other, MaintainabilityRule)
         config = MaintainabilityRuleConfig(
             min(self.config.maintainability_lack_bad, other.config.maintainability_lack_bad),
             min(self.config.maintainability_lack_moderate, other.config.maintainability_lack_moderate),
             min(self.config.maintainability_lack_good, other.config.maintainability_lack_good),
         )
         result_rule = MaintainabilityRule(config)
+        assert self.maintainability_lack is not None
+        assert other.maintainability_lack is not None
         result_rule.apply(max(self.maintainability_lack, other.maintainability_lack))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/method_number_scoring.py b/hyperstyle/src/python/review/quality/rules/method_number_scoring.py
index 0b5c35f5..2e6f79d3 100644
--- a/hyperstyle/src/python/review/quality/rules/method_number_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/method_number_scoring.py
@@ -58,13 +58,16 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: MethodNumberRule) -> MethodNumberRule:
+    def merge(self, other: Rule) -> MethodNumberRule:
+        assert isinstance(other, MethodNumberRule)
         config = MethodNumberRuleConfig(
             min(self.config.method_number_bad, other.config.method_number_bad),
             min(self.config.method_number_moderate, other.config.method_number_moderate),
             min(self.config.method_number_good, other.config.method_number_good),
         )
         result_rule = MethodNumberRule(config)
+        assert self.method_number is not None
+        assert other.method_number is not None
         result_rule.apply(max(self.method_number, other.method_number))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/quality/rules/weighted_methods_scoring.py b/hyperstyle/src/python/review/quality/rules/weighted_methods_scoring.py
index 635f6164..2766e57c 100644
--- a/hyperstyle/src/python/review/quality/rules/weighted_methods_scoring.py
+++ b/hyperstyle/src/python/review/quality/rules/weighted_methods_scoring.py
@@ -56,13 +56,16 @@ def __get_next_quality_type(self) -> QualityType:
             return QualityType.GOOD
         return QualityType.EXCELLENT
 
-    def merge(self, other: WeightedMethodsRule) -> WeightedMethodsRule:
+    def merge(self, other: Rule) -> WeightedMethodsRule:
+        assert isinstance(other, WeightedMethodsRule)
         config = WeightedMethodsRuleConfig(
             min(self.config.weighted_methods_bad, other.config.weighted_methods_bad),
             min(self.config.weighted_methods_moderate, other.config.weighted_methods_moderate),
             min(self.config.weighted_methods_good, other.config.weighted_methods_good),
         )
         result_rule = WeightedMethodsRule(config)
+        assert self.weighted_methods is not None
+        assert other.weighted_methods is not None
         result_rule.apply(max(self.weighted_methods, other.weighted_methods))
 
         return result_rule
diff --git a/hyperstyle/src/python/review/reviewers/common.py b/hyperstyle/src/python/review/reviewers/common.py
index 2e85a328..fa952e95 100644
--- a/hyperstyle/src/python/review/reviewers/common.py
+++ b/hyperstyle/src/python/review/reviewers/common.py
@@ -73,26 +73,28 @@
 }
 
 
-def _inspect_code(
-    metadata: Metadata, config: ApplicationConfig, language: Language
-) -> list[BaseIssue] | None:
+def _inspect_code(metadata: Metadata, config: ApplicationConfig, language: Language) -> list[BaseIssue]:
     inspectors = LANGUAGE_TO_INSPECTORS[language]
-    ij_inspectors = list(
-        filter(
-            lambda inspector: isinstance(inspector, BaseIJInspector)
-            and inspector.inspector_type not in config.disabled_inspectors,
-            inspectors,
-        ),
-    )
+    ij_inspectors: list[BaseIJInspector] = [
+        inspector
+        for inspector in inspectors
+        if (
+            isinstance(inspector, BaseIJInspector)
+            and inspector.inspector_type not in config.disabled_inspectors
+        )
+    ]
 
     connection_parameters = (
         None if config.ij_config is None else json.loads(config.ij_config).get(language.value.lower())
     )
-    if ij_inspectors and connection_parameters is None:
-        msg = f"Connection parameters for {language.value} inspectors are not provided"
-        raise ValueError(msg)
-    for inspector in ij_inspectors:
-        inspector.setup_connection_parameters(connection_parameters["host"], connection_parameters["port"])
+    if ij_inspectors:
+        if connection_parameters is None:
+            msg = f"Connection parameters for {language.value} inspectors are not provided"
+            raise ValueError(msg)
+        for inspector in ij_inspectors:
+            inspector.setup_connection_parameters(
+                connection_parameters["host"], connection_parameters["port"]
+            )
 
     if isinstance(metadata, InMemoryMetadata):
         return inspect_in_parallel(run_inspector_in_memory, metadata.code, config, inspectors)
@@ -110,19 +112,20 @@ def perform_language_review(
         if not config.allow_duplicates:
             issues = filter_duplicate_issues(issues)
 
-    current_files = None
     if isinstance(metadata, FileMetadata):
         current_files = [metadata.path]
         issues = filter_out_of_range_issues(issues, config.start_line, config.end_line)
     elif isinstance(metadata, ProjectMetadata):
         current_files = metadata.language_to_files[language]
+    else:
+        current_files = None
 
     file_path_to_issues = defaultdict(list)
     for issue in issues:
         file_path_to_issues[issue.file_path].append(issue)
 
     if current_files is None:
-        files = file_path_to_issues.keys()
+        files = list(file_path_to_issues.keys())
         current_files = [] if len(files) == 0 else files
 
     previous_issues = get_previous_issues_by_language(config.history, language)
diff --git a/hyperstyle/src/python/review/reviewers/utils/code_statistics.py b/hyperstyle/src/python/review/reviewers/utils/code_statistics.py
index b9b92509..06d97cb4 100644
--- a/hyperstyle/src/python/review/reviewers/utils/code_statistics.py
+++ b/hyperstyle/src/python/review/reviewers/utils/code_statistics.py
@@ -5,7 +5,7 @@
 from typing import TYPE_CHECKING
 
 from hyperstyle.src.python.review.common.file_system import get_total_code_lines_from_file
-from hyperstyle.src.python.review.inspectors.common.issue.issue import BaseIssue, IssueType
+from hyperstyle.src.python.review.inspectors.common.issue.issue import BaseIssue, IssueType, MeasurableIssue
 
 if TYPE_CHECKING:
     from pathlib import Path
@@ -64,7 +64,11 @@ def get_code_style_lines(issues: list[BaseIssue]) -> int:
 
 def __get_max_measure_by_issue_type(issue_type: IssueType, issues: list[BaseIssue]) -> int:
     return max(
-        (issue.measure() for issue in filter(lambda issue: issue.type == issue_type, issues)),
+        (
+            issue.measure() or 0
+            for issue in issues
+            if isinstance(issue, MeasurableIssue) and issue.type == issue_type
+        ),
         default=0,
     )
 
diff --git a/hyperstyle/src/python/review/reviewers/utils/issues_filter.py b/hyperstyle/src/python/review/reviewers/utils/issues_filter.py
index e2848680..bf72dc79 100644
--- a/hyperstyle/src/python/review/reviewers/utils/issues_filter.py
+++ b/hyperstyle/src/python/review/reviewers/utils/issues_filter.py
@@ -7,7 +7,7 @@
     BaseIssue,
     IssueDifficulty,
     IssueType,
-    Measurable,
+    MeasurableIssue,
 )
 from hyperstyle.src.python.review.quality.rules.boolean_length_scoring import (
     LANGUAGE_TO_BOOLEAN_EXPRESSION_RULE_CONFIG,
@@ -60,7 +60,7 @@ def __get_issue_type_to_low_measure_dict(language: Language) -> dict[IssueType,
 def __more_than_low_measure(issue: BaseIssue, issue_type_to_low_measure_dict: dict[IssueType, int]) -> bool:
     issue_type = issue.type
     return not (
-        isinstance(issue, Measurable)
+        isinstance(issue, MeasurableIssue)
         and issue.measure() <= issue_type_to_low_measure_dict.get(issue_type, -1)
     )
 
diff --git a/hyperstyle/src/python/review/reviewers/utils/metadata_exploration.py b/hyperstyle/src/python/review/reviewers/utils/metadata_exploration.py
index 7b8dd334..a37abcb3 100644
--- a/hyperstyle/src/python/review/reviewers/utils/metadata_exploration.py
+++ b/hyperstyle/src/python/review/reviewers/utils/metadata_exploration.py
@@ -29,9 +29,7 @@ class ProjectMetadata:
 
     @property
     def languages(self) -> set[Language]:
-        languages = set()
-        languages.update(file_metadata.language for file_metadata in self.inner_files)
-        return languages
+        return {file_metadata.language for file_metadata in self.inner_files}
 
     @property
     def size_bytes(self) -> int:
diff --git a/hyperstyle/src/python/review/reviewers/utils/print_review.py b/hyperstyle/src/python/review/reviewers/utils/print_review.py
index 007a2fb9..f134daf0 100644
--- a/hyperstyle/src/python/review/reviewers/utils/print_review.py
+++ b/hyperstyle/src/python/review/reviewers/utils/print_review.py
@@ -3,13 +3,10 @@
 import json
 import linecache
 from enum import Enum, unique
-from pathlib import Path
-from typing import Any, TYPE_CHECKING
+from typing import Any, TYPE_CHECKING, TypedDict
 
 from hyperstyle.src.python.review.common.file_system import get_file_line
-from hyperstyle.src.python.review.inspectors.common.inspector.inspector_type import InspectorType
-from hyperstyle.src.python.review.inspectors.common.issue.issue import BaseIssue, IssueDifficulty, IssueType
-from hyperstyle.src.python.review.quality.penalty import PenaltyIssue
+from hyperstyle.src.python.review.inspectors.common.issue.issue import BaseIssue, IssueDifficulty
 from hyperstyle.src.python.review.reviewers.review_result import (
     FileReviewResult,
     GeneralReviewResult,
@@ -17,6 +14,8 @@
 )
 
 if TYPE_CHECKING:
+    from pathlib import Path
+
     from hyperstyle.src.python.review.application_config import ApplicationConfig
     from hyperstyle.src.python.review.quality.model import QualityType
 
@@ -83,9 +82,9 @@ def _get_quality_with_penalty(review_result: ReviewResult) -> dict[IssueDifficul
 
 def get_quality_json_dict(
     quality: dict[IssueDifficulty, QualityType], config: ApplicationConfig
-) -> dict[str, object]:
-    quality_json_dict = {
-        difficulty.value: {
+) -> dict[IssueDifficulty, object] | object:
+    quality_json_dict: dict[IssueDifficulty, object] = {
+        difficulty: {
             OutputJsonFields.CODE.value: quality.value,
             OutputJsonFields.TEXT.value: f"Code quality (beta): {quality.value}",
         }
@@ -95,7 +94,7 @@ def get_quality_json_dict(
     if config.group_by_difficulty:
         return quality_json_dict
 
-    return quality_json_dict[IssueDifficulty.HARD.value]
+    return quality_json_dict[IssueDifficulty.HARD]
 
 
 def get_influence_on_penalty_json_dict(
@@ -106,8 +105,8 @@ def get_influence_on_penalty_json_dict(
     quality_without_penalty = _get_quality_without_penalty(review_result)
     quality_with_penalty = _get_quality_with_penalty(review_result)
 
-    influence_on_penalty_json_dict = {
-        difficulty.value: punisher.get_issue_influence_on_penalty(origin_class)
+    influence_on_penalty_json_dict: dict[IssueDifficulty, int] = {
+        difficulty: punisher.get_issue_influence_on_penalty(origin_class)
         if quality_with_penalty[difficulty] != quality_without_penalty[difficulty]
         else 0
         for difficulty, punisher in review_result.punisher_by_difficulty.items()
@@ -116,25 +115,30 @@ def get_influence_on_penalty_json_dict(
     if config.group_by_difficulty:
         return influence_on_penalty_json_dict
 
-    return influence_on_penalty_json_dict[IssueDifficulty.HARD.value]
+    return influence_on_penalty_json_dict[IssueDifficulty.HARD]
 
 
-def convert_review_result_to_json_dict(
-    review_result: ReviewResult, config: ApplicationConfig
-) -> dict[str, object]:
+class OutputJson(TypedDict):
+    quality: dict[IssueDifficulty, object] | object
+    issues: list[dict[str, object]]
+    file_name: str
+
+
+def convert_review_result_to_json_dict(review_result: ReviewResult, config: ApplicationConfig) -> OutputJson:
     issues = review_result.issues
     issues.sort(key=lambda issue: issue.line_no)
 
     quality_with_penalty = _get_quality_with_penalty(review_result)
 
-    output_json = {}
+    output_json: OutputJson = {
+        OutputJsonFields.QUALITY.value: get_quality_json_dict(quality_with_penalty, config),
+        OutputJsonFields.ISSUES.value: [],
+        OutputJsonFields.FILE_NAME.value: "",
+    }
 
     if isinstance(review_result, FileReviewResult):
         output_json[OutputJsonFields.FILE_NAME.value] = str(review_result.file_path)
 
-    output_json[OutputJsonFields.QUALITY.value] = get_quality_json_dict(quality_with_penalty, config)
-    output_json[OutputJsonFields.ISSUES.value] = []
-
     for issue in issues:
         json_issue = convert_issue_to_json(issue, config)
 
@@ -162,7 +166,7 @@ def print_review_result_as_multi_file_json(
 
 def get_review_result_as_multi_file_json(
     review_result: GeneralReviewResult, config: ApplicationConfig
-) -> dict:
+) -> dict[str, object]:
     review_result.file_review_results.sort(key=lambda result: result.file_path)
 
     file_review_result_jsons = [
@@ -211,23 +215,3 @@ def convert_issue_to_json(issue: BaseIssue, config: ApplicationConfig) -> dict[s
         OutputJsonFields.CATEGORY.value: issue_type.value,
         OutputJsonFields.DIFFICULTY.value: issue.difficulty.value,
     }
-
-
-# It works only for old json format
-def convert_json_to_issues(issues_json: list[dict]) -> list[PenaltyIssue]:
-    return [
-        PenaltyIssue(
-            origin_class=issue[OutputJsonFields.CODE.value],
-            description=issue[OutputJsonFields.TEXT.value],
-            line_no=int(issue[OutputJsonFields.LINE_NUMBER.value]),
-            column_no=int(issue[OutputJsonFields.COLUMN_NUMBER.value]),
-            type=IssueType(issue[OutputJsonFields.CATEGORY.value]),
-            file_path=Path(),
-            inspector_type=InspectorType.UNDEFINED,
-            influence_on_penalty=issue.get(OutputJsonFields.INFLUENCE_ON_PENALTY.value, 0),
-            difficulty=IssueDifficulty(
-                issue.get(OutputJsonFields.DIFFICULTY.value, IssueDifficulty.HARD.value)
-            ),
-        )
-        for issue in issues_json
-    ]
diff --git a/hyperstyle/src/python/review/run_tool.py b/hyperstyle/src/python/review/run_tool.py
index 7fd1bc0e..adfcba06 100644
--- a/hyperstyle/src/python/review/run_tool.py
+++ b/hyperstyle/src/python/review/run_tool.py
@@ -35,7 +35,7 @@ def parse_disabled_inspectors(value: str) -> set[InspectorType]:
     allowed_names = {inspector.value for inspector in InspectorType}
     if not all(name in allowed_names for name in passed_names):
         msg = "disable"
-        raise argparse.ArgumentError(msg, "Incorrect inspectors' names")
+        raise argparse.ArgumentError(msg, "Incorrect inspectors' names")  # type: ignore[arg-type]
 
     return {InspectorType(name) for name in passed_names}
 
@@ -50,7 +50,7 @@ def positive_int(value: str) -> int:
 
 def configure_arguments(parser: argparse.ArgumentParser) -> None:
     parser.add_argument(
-        RunToolArgument.VERBOSITY.value.short_name,
+        RunToolArgument.VERBOSITY.value.short_name,  # type: ignore[arg-type]
         RunToolArgument.VERBOSITY.value.long_name,
         help=RunToolArgument.VERBOSITY.value.description,
         default=VerbosityLevel.DISABLE.value,
@@ -60,7 +60,7 @@ def configure_arguments(parser: argparse.ArgumentParser) -> None:
 
     # Usage example: -d Flake8,IntelliJ
     parser.add_argument(
-        RunToolArgument.DISABLE.value.short_name,
+        RunToolArgument.DISABLE.value.short_name,  # type: ignore[arg-type]
         RunToolArgument.DISABLE.value.long_name,
         help=RunToolArgument.DISABLE.value.description,
         type=parse_disabled_inspectors,
@@ -107,7 +107,7 @@ def configure_arguments(parser: argparse.ArgumentParser) -> None:
     )
 
     parser.add_argument(
-        RunToolArgument.FORMAT.value.short_name,
+        RunToolArgument.FORMAT.value.short_name,  # type: ignore[arg-type]
         RunToolArgument.FORMAT.value.long_name,
         default=OutputFormat.JSON.value,
         choices=OutputFormat.values(),
@@ -116,7 +116,7 @@ def configure_arguments(parser: argparse.ArgumentParser) -> None:
     )
 
     parser.add_argument(
-        RunToolArgument.START_LINE.value.short_name,
+        RunToolArgument.START_LINE.value.short_name,  # type: ignore[arg-type]
         RunToolArgument.START_LINE.value.long_name,
         default=1,
         type=positive_int,
@@ -124,7 +124,7 @@ def configure_arguments(parser: argparse.ArgumentParser) -> None:
     )
 
     parser.add_argument(
-        RunToolArgument.END_LINE.value.short_name,
+        RunToolArgument.END_LINE.value.short_name,  # type: ignore[arg-type]
         RunToolArgument.END_LINE.value.long_name,
         default=None,
         type=positive_int,
diff --git a/poetry.lock b/poetry.lock
index 2a6d46a5..78a9a004 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1228,29 +1228,29 @@ files = [
 
 [[package]]
 name = "ruff"
-version = "0.6.5"
+version = "0.6.7"
 description = "An extremely fast Python linter and code formatter, written in Rust."
 optional = false
 python-versions = ">=3.7"
 files = [
-    {file = "ruff-0.6.5-py3-none-linux_armv6l.whl", hash = "sha256:7e4e308f16e07c95fc7753fc1aaac690a323b2bb9f4ec5e844a97bb7fbebd748"},
-    {file = "ruff-0.6.5-py3-none-macosx_10_12_x86_64.whl", hash = "sha256:932cd69eefe4daf8c7d92bd6689f7e8182571cb934ea720af218929da7bd7d69"},
-    {file = "ruff-0.6.5-py3-none-macosx_11_0_arm64.whl", hash = "sha256:3a8d42d11fff8d3143ff4da41742a98f8f233bf8890e9fe23077826818f8d680"},
-    {file = "ruff-0.6.5-py3-none-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:a50af6e828ee692fb10ff2dfe53f05caecf077f4210fae9677e06a808275754f"},
-    {file = "ruff-0.6.5-py3-none-manylinux_2_17_armv7l.manylinux2014_armv7l.whl", hash = "sha256:794ada3400a0d0b89e3015f1a7e01f4c97320ac665b7bc3ade24b50b54cb2972"},
-    {file = "ruff-0.6.5-py3-none-manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:381413ec47f71ce1d1c614f7779d88886f406f1fd53d289c77e4e533dc6ea200"},
-    {file = "ruff-0.6.5-py3-none-manylinux_2_17_ppc64.manylinux2014_ppc64.whl", hash = "sha256:52e75a82bbc9b42e63c08d22ad0ac525117e72aee9729a069d7c4f235fc4d276"},
-    {file = "ruff-0.6.5-py3-none-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl", hash = "sha256:09c72a833fd3551135ceddcba5ebdb68ff89225d30758027280968c9acdc7810"},
-    {file = "ruff-0.6.5-py3-none-manylinux_2_17_s390x.manylinux2014_s390x.whl", hash = "sha256:800c50371bdcb99b3c1551d5691e14d16d6f07063a518770254227f7f6e8c178"},
-    {file = "ruff-0.6.5-py3-none-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:8e25ddd9cd63ba1f3bd51c1f09903904a6adf8429df34f17d728a8fa11174253"},
-    {file = "ruff-0.6.5-py3-none-musllinux_1_2_aarch64.whl", hash = "sha256:7291e64d7129f24d1b0c947ec3ec4c0076e958d1475c61202497c6aced35dd19"},
-    {file = "ruff-0.6.5-py3-none-musllinux_1_2_armv7l.whl", hash = "sha256:9ad7dfbd138d09d9a7e6931e6a7e797651ce29becd688be8a0d4d5f8177b4b0c"},
-    {file = "ruff-0.6.5-py3-none-musllinux_1_2_i686.whl", hash = "sha256:005256d977021790cc52aa23d78f06bb5090dc0bfbd42de46d49c201533982ae"},
-    {file = "ruff-0.6.5-py3-none-musllinux_1_2_x86_64.whl", hash = "sha256:482c1e6bfeb615eafc5899127b805d28e387bd87db38b2c0c41d271f5e58d8cc"},
-    {file = "ruff-0.6.5-py3-none-win32.whl", hash = "sha256:cf4d3fa53644137f6a4a27a2b397381d16454a1566ae5335855c187fbf67e4f5"},
-    {file = "ruff-0.6.5-py3-none-win_amd64.whl", hash = "sha256:3e42a57b58e3612051a636bc1ac4e6b838679530235520e8f095f7c44f706ff9"},
-    {file = "ruff-0.6.5-py3-none-win_arm64.whl", hash = "sha256:51935067740773afdf97493ba9b8231279e9beef0f2a8079188c4776c25688e0"},
-    {file = "ruff-0.6.5.tar.gz", hash = "sha256:4d32d87fab433c0cf285c3683dd4dae63be05fd7a1d65b3f5bf7cdd05a6b96fb"},
+    {file = "ruff-0.6.7-py3-none-linux_armv6l.whl", hash = "sha256:08277b217534bfdcc2e1377f7f933e1c7957453e8a79764d004e44c40db923f2"},
+    {file = "ruff-0.6.7-py3-none-macosx_10_12_x86_64.whl", hash = "sha256:c6707a32e03b791f4448dc0dce24b636cbcdee4dd5607adc24e5ee73fd86c00a"},
+    {file = "ruff-0.6.7-py3-none-macosx_11_0_arm64.whl", hash = "sha256:533d66b7774ef224e7cf91506a7dafcc9e8ec7c059263ec46629e54e7b1f90ab"},
+    {file = "ruff-0.6.7-py3-none-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:17a86aac6f915932d259f7bec79173e356165518859f94649d8c50b81ff087e9"},
+    {file = "ruff-0.6.7-py3-none-manylinux_2_17_armv7l.manylinux2014_armv7l.whl", hash = "sha256:b3f8822defd260ae2460ea3832b24d37d203c3577f48b055590a426a722d50ef"},
+    {file = "ruff-0.6.7-py3-none-manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:9ba4efe5c6dbbb58be58dd83feedb83b5e95c00091bf09987b4baf510fee5c99"},
+    {file = "ruff-0.6.7-py3-none-manylinux_2_17_ppc64.manylinux2014_ppc64.whl", hash = "sha256:525201b77f94d2b54868f0cbe5edc018e64c22563da6c5c2e5c107a4e85c1c0d"},
+    {file = "ruff-0.6.7-py3-none-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl", hash = "sha256:8854450839f339e1049fdbe15d875384242b8e85d5c6947bb2faad33c651020b"},
+    {file = "ruff-0.6.7-py3-none-manylinux_2_17_s390x.manylinux2014_s390x.whl", hash = "sha256:2f0b62056246234d59cbf2ea66e84812dc9ec4540518e37553513392c171cb18"},
+    {file = "ruff-0.6.7-py3-none-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:6b1462fa56c832dc0cea5b4041cfc9c97813505d11cce74ebc6d1aae068de36b"},
+    {file = "ruff-0.6.7-py3-none-musllinux_1_2_aarch64.whl", hash = "sha256:02b083770e4cdb1495ed313f5694c62808e71764ec6ee5db84eedd82fd32d8f5"},
+    {file = "ruff-0.6.7-py3-none-musllinux_1_2_armv7l.whl", hash = "sha256:0c05fd37013de36dfa883a3854fae57b3113aaa8abf5dea79202675991d48624"},
+    {file = "ruff-0.6.7-py3-none-musllinux_1_2_i686.whl", hash = "sha256:f49c9caa28d9bbfac4a637ae10327b3db00f47d038f3fbb2195c4d682e925b14"},
+    {file = "ruff-0.6.7-py3-none-musllinux_1_2_x86_64.whl", hash = "sha256:a0e1655868164e114ba43a908fd2d64a271a23660195017c17691fb6355d59bb"},
+    {file = "ruff-0.6.7-py3-none-win32.whl", hash = "sha256:a939ca435b49f6966a7dd64b765c9df16f1faed0ca3b6f16acdf7731969deb35"},
+    {file = "ruff-0.6.7-py3-none-win_amd64.whl", hash = "sha256:590445eec5653f36248584579c06252ad2e110a5d1f32db5420de35fb0e1c977"},
+    {file = "ruff-0.6.7-py3-none-win_arm64.whl", hash = "sha256:b28f0d5e2f771c1fe3c7a45d3f53916fc74a480698c4b5731f0bea61e52137c8"},
+    {file = "ruff-0.6.7.tar.gz", hash = "sha256:44e52129d82266fa59b587e2cd74def5637b730a69c4542525dfdecfaae38bd5"},
 ]
 
 [[package]]
@@ -1307,6 +1307,17 @@ files = [
     {file = "tomli-2.0.1.tar.gz", hash = "sha256:de526c12914f0c550d15924c62d72abc48d6fe7364aa87328337a31007fe8a4f"},
 ]
 
+[[package]]
+name = "types-protobuf"
+version = "5.28.0.20240924"
+description = "Typing stubs for protobuf"
+optional = false
+python-versions = ">=3.8"
+files = [
+    {file = "types-protobuf-5.28.0.20240924.tar.gz", hash = "sha256:d181af8a256e5a91ce8d5adb53496e880efd9144c7d54483e3653332b60296f0"},
+    {file = "types_protobuf-5.28.0.20240924-py3-none-any.whl", hash = "sha256:5cecf612ccdefb7dc95f7a51fb502902f20fc2e6681cd500184aaa1b3931d6a7"},
+]
+
 [[package]]
 name = "typing-extensions"
 version = "3.10.0.2"
@@ -1336,13 +1347,13 @@ typing-extensions = ">=3.7.4"
 
 [[package]]
 name = "tzdata"
-version = "2024.1"
+version = "2024.2"
 description = "Provider of IANA time zone data"
 optional = false
 python-versions = ">=2"
 files = [
-    {file = "tzdata-2024.1-py2.py3-none-any.whl", hash = "sha256:9068bc196136463f5245e51efda838afa15aaeca9903f49050dfa2679db4d252"},
-    {file = "tzdata-2024.1.tar.gz", hash = "sha256:2674120f8d891909751c38abcdfd386ac0a5a1127954fbc332af6b5ceae07efd"},
+    {file = "tzdata-2024.2-py2.py3-none-any.whl", hash = "sha256:a48093786cdcde33cad18c2555e8532f34422074448fbc874186f0abd79565cd"},
+    {file = "tzdata-2024.2.tar.gz", hash = "sha256:7d85cc416e9382e69095b7bdf4afd9e3880418a2413feec7069d533d6b4e31cc"},
 ]
 
 [[package]]
@@ -1463,4 +1474,4 @@ files = [
 [metadata]
 lock-version = "2.0"
 python-versions = "~3.10"
-content-hash = "9db75465afe75cbcef197a6aed301dd091eb6d71d5fe460103ff74e8fa35a8e4"
+content-hash = "617a81c3d550e69a35f583bb892200431fd63925ca4728c886ec63f07be8625f"
diff --git a/pyproject.toml b/pyproject.toml
index 858b15f1..7af8e03f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -65,7 +65,8 @@ mypy = "1.3.0"
 pytest = "8.3.3"
 pytest-runner = "6.0.1"
 pytest-subtests = "0.13.1"
-ruff = "0.6.5"
+ruff = "0.6.7"
+types-protobuf = "5.28.0.20240924"
 
 [build-system]
 requires = ["poetry-core"]
diff --git a/test/python/inspectors/test_filter_duplicate_issues.py b/test/python/inspectors/test_filter_duplicate_issues.py
index e815dfca..0b7d351c 100644
--- a/test/python/inspectors/test_filter_duplicate_issues.py
+++ b/test/python/inspectors/test_filter_duplicate_issues.py
@@ -3,12 +3,17 @@
 from pathlib import Path
 
 from hyperstyle.src.python.review.inspectors.common.inspector.inspector_type import InspectorType
-from hyperstyle.src.python.review.inspectors.common.issue.issue import CodeIssue, IssueDifficulty, IssueType
+from hyperstyle.src.python.review.inspectors.common.issue.issue import (
+    BaseIssue,
+    CodeIssue,
+    IssueDifficulty,
+    IssueType,
+)
 from hyperstyle.src.python.review.reviewers.utils.issues_filter import filter_duplicate_issues
 
 
 def test_filter_duplicate_issues_when_single_inspector() -> None:
-    issues = [
+    issues: list[BaseIssue] = [
         CodeIssue(
             file_path=Path("code.py"),
             line_no=10,
@@ -57,7 +62,7 @@ def test_filter_duplicate_issues_when_single_inspector() -> None:
 
 
 def test_filter_duplicate_issues_when_several_inspectors() -> None:
-    issues = [
+    issues: list[BaseIssue] = [
         CodeIssue(
             file_path=Path("code.py"),
             line_no=10,
@@ -106,7 +111,7 @@ def test_filter_duplicate_issues_when_several_inspectors() -> None:
 
 
 def test_filter_duplicate_issues_when_several_issues_in_line_no() -> None:
-    issues = [
+    issues: list[BaseIssue] = [
         CodeIssue(
             file_path=Path("code.py"),
             line_no=10,
diff --git a/test/python/inspectors/test_issue_configs.py b/test/python/inspectors/test_issue_configs.py
index 7e6137d9..1069fb61 100644
--- a/test/python/inspectors/test_issue_configs.py
+++ b/test/python/inspectors/test_issue_configs.py
@@ -131,7 +131,7 @@ def test_init_raises_exception(
     expected_error_message: str,
 ) -> None:
     with pytest.raises(expected_exception) as excinfo:
-        cls(*args)
+        cls(*args)  # type: ignore[arg-type]
 
     assert str(excinfo.value) == expected_error_message