René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: FuncAnimation function not typed properly","articleBody":"### Bug summary\n\nType checkers complain when one uses a function that returns `None` as the parameter of `FuncAnimation`. However, when `blit=False`, the return value of the function is ignored.\n\n### Code for reproduction\n\n```Python\nimport matplotlib.pyplot as plt\nfrom matplotlib import rc\nfrom matplotlib.animation import FuncAnimation\n\nrc(\"animation\", html=\"jshtml\")\n\nfig, ax = plt.subplots()\n\ndef update(frame: int) -\u003e None:\n    ax.plot([0, 1], [frame, frame])\n\nFuncAnimation(fig, update, range(10))\n```\n\n### Actual outcome\n\nMyPy says `Argument 2 to \"FuncAnimation\" has incompatible type \"Callable[[int], None]\"; expected \"Callable[..., Iterable[Artist]]\"`, but the code executes without problems.\n\n### Expected outcome\n\nNo MyPy error.\n\n### Additional information\n\nI think is possible to allow functions that return arbitrary `object` by combining `overload` and `Literal[True]` / `Literal[False]` for the `blit` argument.\n\n### Operating system\n\nAny\n\n### Matplotlib Version\n\n3.10.0\n\n### Matplotlib Backend\n\n_No response_\n\n### Python version\n\n_No response_\n\n### Jupyter version\n\n_No response_\n\n### Installation\n\npip","author":{"url":"https://github.com/vnmabus","@type":"Person","name":"vnmabus"},"datePublished":"2025-04-22T18:29:38.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":12},"url":"https://github.com/29960/matplotlib/issues/29960"}