Fix Typing

manim/mobject/mobject.py

@@ -21,7 +21,8 @@
     Iterable,
     TypeVar,
     Literal,
-    Self
+    Self,
+    Never
 )
 
 import numpy as np
@@ -2755,7 +2756,7 @@ def construct(self):
         return self
 
     # Errors
-    def throw_error_if_no_points(self) -> None:
+    def throw_error_if_no_points(self) -> None | Never:
         if self.has_no_points():
             caller_name = sys._getframe(1).f_code.co_name
             raise Exception(

manim/mobject/three_d/three_d_utils.py

@@ -15,39 +15,43 @@
 
 
 import numpy as np
+from typing import Literal, TYPE_CHECKING
 
 from manim.constants import ORIGIN, UP
 from manim.utils.space_ops import get_unit_normal
 
+if TYPE_CHECKING:
+    from manim.typing import Point3D, Vector
 
-def get_3d_vmob_gradient_start_and_end_points(vmob):
+
+def get_3d_vmob_gradient_start_and_end_points(vmob) -> tuple[Point3D, Point3D]:
     return (
         get_3d_vmob_start_corner(vmob),
         get_3d_vmob_end_corner(vmob),
     )
 
 
-def get_3d_vmob_start_corner_index(vmob):
+def get_3d_vmob_start_corner_index(vmob) -> Literal[0]:
     return 0
 
 
-def get_3d_vmob_end_corner_index(vmob):
+def get_3d_vmob_end_corner_index(vmob) -> int:
     return ((len(vmob.points) - 1) // 6) * 3
 
 
-def get_3d_vmob_start_corner(vmob):
+def get_3d_vmob_start_corner(vmob) -> Point3D:
     if vmob.get_num_points() == 0:
         return np.array(ORIGIN)
     return vmob.points[get_3d_vmob_start_corner_index(vmob)]
 
 
-def get_3d_vmob_end_corner(vmob):
+def get_3d_vmob_end_corner(vmob) -> Point3D:
     if vmob.get_num_points() == 0:
         return np.array(ORIGIN)
     return vmob.points[get_3d_vmob_end_corner_index(vmob)]
 
 
-def get_3d_vmob_unit_normal(vmob, point_index):
+def get_3d_vmob_unit_normal(vmob, point_index: int) -> Vector:
     n_points = vmob.get_num_points()
     if len(vmob.get_anchors()) <= 2:
         return np.array(UP)
@@ -63,9 +67,9 @@ def get_3d_vmob_unit_normal(vmob, point_index):
     return unit_normal
 
 
-def get_3d_vmob_start_corner_unit_normal(vmob):
+def get_3d_vmob_start_corner_unit_normal(vmob) -> Vector:
     return get_3d_vmob_unit_normal(vmob, get_3d_vmob_start_corner_index(vmob))
 
 
-def get_3d_vmob_end_corner_unit_normal(vmob):
+def get_3d_vmob_end_corner_unit_normal(vmob) -> Vector:
     return get_3d_vmob_unit_normal(vmob, get_3d_vmob_end_corner_index(vmob))