Added type hints

src/PIL/ImageSequence.py

@@ -16,6 +16,10 @@
 ##
 from __future__ import annotations
 
+from typing import Callable
+
+from . import Image
+
 
 class Iterator:
     """
@@ -29,25 +33,25 @@ class Iterator:
     :param im: An image object.
     """
 
-    def __init__(self, im):
+    def __init__(self, im: Image.Image):
         if not hasattr(im, "seek"):
             msg = "im must have seek method"
             raise AttributeError(msg)
         self.im = im
         self.position = getattr(self.im, "_min_frame", 0)
 
-    def __getitem__(self, ix):
+    def __getitem__(self, ix: int) -> Image.Image:
         try:
             self.im.seek(ix)
             return self.im
         except EOFError as e:
             msg = "end of sequence"
             raise IndexError(msg) from e
 
-    def __iter__(self):
+    def __iter__(self) -> Iterator:
         return self
 
-    def __next__(self):
+    def __next__(self) -> Image.Image:
         try:
             self.im.seek(self.position)
             self.position += 1
@@ -57,7 +61,10 @@ def __next__(self):
             raise StopIteration(msg) from e
 
 
-def all_frames(im, func=None):
+def all_frames(
+    im: Image.Image | list[Image.Image],
+    func: Callable[[Image.Image], Image.Image] | None = None,
+) -> list[Image.Image]:
     """
     Applies a given function to all frames in an image or a list of images.
     The frames are returned as a list of separate images.