Add decorator

Author: JasonGrace2282

manim/utils/decorators.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, TypeVar
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+    from typing_extensions import ParamSpec
+
+    P = ParamSpec("P")
+    T = TypeVar("T")
+
+
+def internal(f: Callable[P, T]) -> Callable[P, T]:
+    """
+    This decorator marks a function as internal
+    by adding a warning to the docstring of the object.
+
+    Note that usage on a method starting with an underscore
+    has no effect, as sphinx does not document such methods
+
+    .. code-block:: python
+
+        @internal
+        def some_private_method(self):
+            # does some private stuff
+            ...
+
+
+        @internal  # does not do anything, don't use
+        def _my_second_private_method(self): ...
+    """
+    doc: str = f.__doc__ if f.__doc__ is not None else ""
+    newblockline = "\n    "
+    directive = f".. warning::{newblockline}"
+    directive += newblockline.join(
+        (
+            "This method is designed for internal use",
+            "and may not stay the same in future versions of Manim",
+        )
+    )
+    f.__doc__ = f"{directive}\n\n{doc}"
+    return f