Treat Group and VGroup more like list types

This may not be the best way to address it, but at least temporarily it prevents linting issues for calls like VGroup(Circle())[0].get_radius()

manimlib/mobject/mobject.py

@@ -48,7 +48,7 @@
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
-    from typing import Callable, Iterable, Iterator, Union, Tuple, Optional, TypeVar
+    from typing import Callable, Iterable, Iterator, Union, Tuple, Optional, TypeVar, Generic, List
     import numpy.typing as npt
     from manimlib.typing import ManimColor, Vect3, Vect4, Vect3Array, UniformDict, Self
     from moderngl.context import Context
@@ -57,6 +57,7 @@
     TimeBasedUpdater = Callable[["Mobject", float], "Mobject" | None]
     NonTimeUpdater = Callable[["Mobject"], "Mobject" | None]
     Updater = Union[TimeBasedUpdater, NonTimeUpdater]
+    SubmobjectType = TypeVar('SubmobjectType', bound='Mobject')
 
 
 class Mobject(object):
@@ -352,7 +353,7 @@ def is_touching(self, mobject: Mobject, buff: float = 1e-2) -> bool:
 
     # Family matters
 
-    def __getitem__(self, value: int | slice) -> Self:
+    def __getitem__(self, value: int | slice) -> Mobject:
         if isinstance(value, slice):
             GroupClass = self.get_group_class()
             return GroupClass(*self.split().__getitem__(value))
@@ -2132,8 +2133,8 @@ def throw_error_if_no_points(self):
             raise Exception(message.format(caller_name))
 
 
-class Group(Mobject):
-    def __init__(self, *mobjects: Mobject, **kwargs):
+class Group(Mobject, Generic[SubmobjectType]):
+    def __init__(self, *mobjects: SubmobjectType, **kwargs):
         if not all([isinstance(m, Mobject) for m in mobjects]):
             raise Exception("All submobjects must be of type Mobject")
         super().__init__(**kwargs)
@@ -2143,6 +2144,9 @@ def __add__(self, other: Mobject | Group) -> Self:
         assert isinstance(other, Mobject)
         return self.add(other)
 
+    # This is just here to make linters happy with references to things like Group(...)[0]
+    def __getitem__(self, index) -> SubmobjectType:
+        return super().__getitem__(index)
 
 
 class Point(Mobject):

manimlib/mobject/types/vectorized_mobject.py

@@ -50,13 +50,15 @@
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
-    from typing import Callable, Iterable, Tuple, Any
+    from typing import Callable, Iterable, Tuple, Any, Generic, TypeVar
     from manimlib.typing import ManimColor, Vect3, Vect4, Vect3Array, Vect4Array, Self
     from moderngl.context import Context
+    SubVmobjectType = TypeVar('SubVmobjectType', bound='VMobject')
 
 DEFAULT_STROKE_COLOR = GREY_A
 DEFAULT_FILL_COLOR = GREY_C
 
+
 class VMobject(Mobject):
     fill_shader_folder: str = "quadratic_bezier_fill"
     stroke_shader_folder: str = "quadratic_bezier_stroke"
@@ -1415,8 +1417,8 @@ def get_shader_wrapper_list(self, ctx: Context) -> list[ShaderWrapper]:
         return [sw for sw in shader_wrappers if len(sw.vert_data) > 0]
 
 
-class VGroup(VMobject):
-    def __init__(self, *vmobjects: VMobject, **kwargs):
+class VGroup(VMobject, Generic[SubVmobjectType]):
+    def __init__(self, *vmobjects: SubVmobjectType, **kwargs):
         super().__init__(**kwargs)
         self.add(*vmobjects)
         if vmobjects:
@@ -1426,6 +1428,10 @@ def __add__(self, other: VMobject) -> Self:
         assert isinstance(other, VMobject)
         return self.add(other)
 
+    # This is just here to make linters happy with references to things like VGroup(...)[0]
+    def __getitem__(self, index) -> SubVmobjectType:
+        return super().__getitem__(index)
+
 
 class VectorizedPoint(Point, VMobject):
     def __init__(