Bug summary

Type 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.

Code for reproduction

import matplotlib.pyplot as plt
from matplotlib import rc
from matplotlib.animation import FuncAnimation

rc("animation", html="jshtml")

fig, ax = plt.subplots()

def update(frame: int) -> None:
    ax.plot([0, 1], [frame, frame])

FuncAnimation(fig, update, range(10))

Actual outcome

MyPy says Argument 2 to "FuncAnimation" has incompatible type "Callable[[int], None]"; expected "Callable[..., Iterable[Artist]]", but the code executes without problems.

Expected outcome

No MyPy error.

Additional information

I think is possible to allow functions that return arbitrary object by combining overload and Literal[True] / Literal[False] for the blit argument.

Operating system

Any

Matplotlib Version

3.10.0

Matplotlib Backend

No response

Python version

No response

Jupyter version

No response

Installation

pip