diff --git a/tutorials/02_navier_stokes/tutorial_navier_stokes.ipynb b/tutorials/02_navier_stokes/tutorial_navier_stokes.ipynb
index 8a408dd..fed16a1 100644
--- a/tutorials/02_navier_stokes/tutorial_navier_stokes.ipynb
+++ b/tutorials/02_navier_stokes/tutorial_navier_stokes.ipynb
@@ -168,9 +168,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_interface.ipynb b/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_interface.ipynb
index c9f5ee2..f7560d8 100644
--- a/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_interface.ipynb
+++ b/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_interface.ipynb
@@ -155,9 +155,11 @@
    "outputs": [],
    "source": [
     "partitioner = dolfinx.mesh.create_cell_partitioner(dolfinx.mesh.GhostMode.shared_facet)\n",
-    "mesh, subdomains, boundaries_and_interfaces = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries_and_interfaces, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2, partitioner=partitioner)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries_and_interfaces is not None"
    ]
   },
   {
diff --git a/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_linear.ipynb b/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_linear.ipynb
index 8fa36fb..5c68883 100644
--- a/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_linear.ipynb
+++ b/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_linear.ipynb
@@ -149,9 +149,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_nonlinear.ipynb b/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_nonlinear.ipynb
index 0bf6bb1..62699a9 100644
--- a/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_nonlinear.ipynb
+++ b/tutorials/03_lagrange_multipliers/tutorial_lagrange_multipliers_nonlinear.ipynb
@@ -166,9 +166,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/04_eigenvalue_problems/tutorial_eigenvalue_laplacian.ipynb b/tutorials/04_eigenvalue_problems/tutorial_eigenvalue_laplacian.ipynb
index d2456be..2866ad9 100644
--- a/tutorials/04_eigenvalue_problems/tutorial_eigenvalue_laplacian.ipynb
+++ b/tutorials/04_eigenvalue_problems/tutorial_eigenvalue_laplacian.ipynb
@@ -140,9 +140,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/04_eigenvalue_problems/tutorial_infsup_lagrange_multipliers.ipynb b/tutorials/04_eigenvalue_problems/tutorial_infsup_lagrange_multipliers.ipynb
index e5a19aa..0ad44f3 100644
--- a/tutorials/04_eigenvalue_problems/tutorial_infsup_lagrange_multipliers.ipynb
+++ b/tutorials/04_eigenvalue_problems/tutorial_infsup_lagrange_multipliers.ipynb
@@ -133,9 +133,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/06_optimal_control/tutorial_1b_poisson.ipynb b/tutorials/06_optimal_control/tutorial_1b_poisson.ipynb
index d2f9ef3..7c6dcc1 100644
--- a/tutorials/06_optimal_control/tutorial_1b_poisson.ipynb
+++ b/tutorials/06_optimal_control/tutorial_1b_poisson.ipynb
@@ -150,9 +150,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/06_optimal_control/tutorial_2b_advection_diffusion_reaction.ipynb b/tutorials/06_optimal_control/tutorial_2b_advection_diffusion_reaction.ipynb
index dfc9ef7..5975471 100644
--- a/tutorials/06_optimal_control/tutorial_2b_advection_diffusion_reaction.ipynb
+++ b/tutorials/06_optimal_control/tutorial_2b_advection_diffusion_reaction.ipynb
@@ -218,9 +218,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/06_optimal_control/tutorial_3b_advection_diffusion_reaction_neumann_control.ipynb b/tutorials/06_optimal_control/tutorial_3b_advection_diffusion_reaction_neumann_control.ipynb
index 416f9ee..c26a729 100644
--- a/tutorials/06_optimal_control/tutorial_3b_advection_diffusion_reaction_neumann_control.ipynb
+++ b/tutorials/06_optimal_control/tutorial_3b_advection_diffusion_reaction_neumann_control.ipynb
@@ -213,9 +213,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/06_optimal_control/tutorial_7a_stokes_dirichlet_control.ipynb b/tutorials/06_optimal_control/tutorial_7a_stokes_dirichlet_control.ipynb
index d527e34..e44fc0f 100644
--- a/tutorials/06_optimal_control/tutorial_7a_stokes_dirichlet_control.ipynb
+++ b/tutorials/06_optimal_control/tutorial_7a_stokes_dirichlet_control.ipynb
@@ -210,9 +210,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/06_optimal_control/tutorial_7b_stokes_neumann_control.ipynb b/tutorials/06_optimal_control/tutorial_7b_stokes_neumann_control.ipynb
index 9a37c89..4ee693d 100644
--- a/tutorials/06_optimal_control/tutorial_7b_stokes_neumann_control.ipynb
+++ b/tutorials/06_optimal_control/tutorial_7b_stokes_neumann_control.ipynb
@@ -201,9 +201,11 @@
    "outputs": [],
    "source": [
     "partitioner = dolfinx.mesh.create_cell_partitioner(dolfinx.mesh.GhostMode.shared_facet)\n",
-    "mesh, subdomains, boundaries_and_interfaces = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries_and_interfaces, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2, partitioner=partitioner)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries_and_interfaces is not None"
    ]
   },
   {
diff --git a/tutorials/07_understanding_restrictions/tutorial_understanding_restrictions.ipynb b/tutorials/07_understanding_restrictions/tutorial_understanding_restrictions.ipynb
index 890a213..d504b18 100644
--- a/tutorials/07_understanding_restrictions/tutorial_understanding_restrictions.ipynb
+++ b/tutorials/07_understanding_restrictions/tutorial_understanding_restrictions.ipynb
@@ -311,9 +311,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mesh, subdomains, boundaries = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries is not None"
    ]
   },
   {
diff --git a/tutorials/08_singular_poisson/tutorial_create_nullspace.ipynb b/tutorials/08_singular_poisson/tutorial_create_nullspace.ipynb
index 4f65532..a9bd07a 100644
--- a/tutorials/08_singular_poisson/tutorial_create_nullspace.ipynb
+++ b/tutorials/08_singular_poisson/tutorial_create_nullspace.ipynb
@@ -142,9 +142,11 @@
    "outputs": [],
    "source": [
     "partitioner = dolfinx.mesh.create_cell_partitioner(dolfinx.mesh.GhostMode.shared_facet)\n",
-    "mesh, subdomains, boundaries_and_interfaces = dolfinx.io.gmshio.model_to_mesh(\n",
+    "mesh, subdomains, boundaries_and_interfaces, *_ = dolfinx.io.gmshio.model_to_mesh(\n",
     "    gmsh.model, comm=mpi4py.MPI.COMM_WORLD, rank=0, gdim=2, partitioner=partitioner)\n",
-    "gmsh.finalize()"
+    "gmsh.finalize()\n",
+    "assert subdomains is not None\n",
+    "assert boundaries_and_interfaces is not None"
    ]
   },
   {