diff --git a/pyproject.toml b/pyproject.toml
index 9db4655c..a22fcb95 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -124,6 +124,7 @@ plugins = [
 ]
 strict = true
 warn_return_any = false
+warn_unreachable = true
 
 [tool.pytest.ini_options]
 addopts = [
diff --git a/src/sleplet/functions/slepian.py b/src/sleplet/functions/slepian.py
index e5a579c1..e0d28f82 100644
--- a/src/sleplet/functions/slepian.py
+++ b/src/sleplet/functions/slepian.py
@@ -82,9 +82,6 @@ def _check_rank(
         cls,  # noqa: ANN101
         v: int,
     ) -> int:
-        if not isinstance(v, int):
-            msg = "rank should be an integer"
-            raise TypeError(msg)
         if v < 0:
             msg = "rank cannot be negative"
             raise ValueError(msg)
diff --git a/src/sleplet/functions/spherical_harmonic.py b/src/sleplet/functions/spherical_harmonic.py
index 8f01c6e5..998b0288 100644
--- a/src/sleplet/functions/spherical_harmonic.py
+++ b/src/sleplet/functions/spherical_harmonic.py
@@ -55,9 +55,6 @@ def _check_ell(
         v: int,
         info: pydantic.ValidationInfo,
     ) -> int:
-        if not isinstance(v, int):
-            msg = "ell should be an integer"
-            raise TypeError(msg)
         if v < 0:
             msg = "ell should be positive"
             raise ValueError(msg)
@@ -72,9 +69,6 @@ def _check_m(
         v: int,
         info: pydantic.ValidationInfo,
     ) -> int:
-        if not isinstance(v, int):
-            msg = "m should be an integer"
-            raise TypeError(msg)
         if abs(v) > info.data["ell"]:
             msg = "the magnitude of m should be less than ell"
             raise ValueError(msg)
diff --git a/src/sleplet/meshes/_mesh_slepian_decomposition.py b/src/sleplet/meshes/_mesh_slepian_decomposition.py
index 3809b9f7..94160194 100644
--- a/src/sleplet/meshes/_mesh_slepian_decomposition.py
+++ b/src/sleplet/meshes/_mesh_slepian_decomposition.py
@@ -117,9 +117,6 @@ def _detect_method(self: typing_extensions.Self) -> None:
 
     def _validate_rank(self: typing_extensions.Self, rank: int) -> None:
         """Check the requested rank is valid."""
-        if not isinstance(rank, int):
-            msg = "rank should be an integer"
-            raise TypeError(msg)
         if rank < 0:
             msg = "rank cannot be negative"
             raise ValueError(msg)
diff --git a/src/sleplet/meshes/mesh_basis_functions.py b/src/sleplet/meshes/mesh_basis_functions.py
index a29d46d1..1d4630ad 100644
--- a/src/sleplet/meshes/mesh_basis_functions.py
+++ b/src/sleplet/meshes/mesh_basis_functions.py
@@ -69,9 +69,6 @@ def _check_rank(
         cls,  # noqa: ANN101
         v: int,
     ) -> int:
-        if not isinstance(v, int):
-            msg = "rank should be an integer"
-            raise TypeError(msg)
         if v < 0:
             msg = "rank cannot be negative"
             raise ValueError(msg)
diff --git a/src/sleplet/meshes/mesh_slepian_functions.py b/src/sleplet/meshes/mesh_slepian_functions.py
index 1bd29a73..788287ed 100644
--- a/src/sleplet/meshes/mesh_slepian_functions.py
+++ b/src/sleplet/meshes/mesh_slepian_functions.py
@@ -71,9 +71,6 @@ def _check_rank(
         cls,  # noqa: ANN101
         v: int,
     ) -> int:
-        if not isinstance(v, int):
-            msg = "rank should be an integer"
-            raise TypeError(msg)
         if v < 0:
             msg = "rank cannot be negative"
             raise ValueError(msg)
diff --git a/src/sleplet/slepian/_slepian_decomposition.py b/src/sleplet/slepian/_slepian_decomposition.py
index ee14ed4c..79ac2948 100644
--- a/src/sleplet/slepian/_slepian_decomposition.py
+++ b/src/sleplet/slepian/_slepian_decomposition.py
@@ -123,9 +123,6 @@ def _detect_method(self: typing_extensions.Self) -> None:
 
     def _validate_rank(self: typing_extensions.Self, rank: int) -> None:
         """Check the requested rank is valid."""
-        if not isinstance(rank, int):
-            msg = "rank should be an integer"
-            raise TypeError(msg)
         if rank < 0:
             msg = "rank cannot be negative"
             raise ValueError(msg)