fix mypy error in sets.py: cast(Sequence[Sequence[float]], kpoints)

pymatgen/io/vasp/sets.py

@@ -34,12 +34,13 @@
 import re
 import shutil
 import warnings
+from collections.abc import Sequence
 from copy import deepcopy
 from dataclasses import dataclass, field
 from glob import glob
 from itertools import chain
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, Literal, Union
+from typing import TYPE_CHECKING, Any, Literal, Union, cast
 from zipfile import ZipFile
 
 import numpy as np
@@ -58,8 +59,6 @@
 from pymatgen.util.due import Doi, due
 
 if TYPE_CHECKING:
-    from collections.abc import Sequence
-
     from typing_extensions import Self
 
     from pymatgen.core.trajectory import Vector3D
@@ -3072,9 +3071,7 @@ def _get_ispin(vasprun: Vasprun | None, outcar: Outcar | None) -> int:
 
 def _combine_kpoints(*kpoints_objects: Kpoints) -> Kpoints:
     """Combine k-points files together."""
-    labels = []
-    kpoints = []
-    weights = []
+    labels, kpoints, weights = [], [], []
 
     for kpoints_object in filter(None, kpoints_objects):
         if kpoints_object.style != Kpoints.supported_modes.Reciprocal:
@@ -3094,7 +3091,7 @@ def _combine_kpoints(*kpoints_objects: Kpoints) -> Kpoints:
         comment="Combined k-points",
         style=Kpoints.supported_modes.Reciprocal,
         num_kpts=len(kpoints),
-        kpts=kpoints,
+        kpts=cast(Sequence[Sequence[float]], kpoints),
         labels=labels,
         kpts_weights=weights,
     )