[Python] How to add type hints for an optional dependency in Python? [duplicate]

In a Python package, matplotlib is used only in one function and hence, is defined as an optional dependency. This function takes an optional ax-argument.

def my_plot_function(ax=None):

if ax is None:
import matplotlib.pyplot as plt

fig, ax = plt.subplots()

# plot someting...

return ax


What is the best way to add type hints without making matplotlib a required dependency? Is this possible with some fake types in case matplotlib is not installed?

from matplotlib.axes import Axes

def my_plot_function(ax : None | Axes = None) -> Axes:

if ax is None:
import matplotlib.pyplot as plt

fig, ax = plt.subplots()

# plot someting...

return ax


Would

try:
from matplotlib.axes import Axes

except ModuleNotFoundError:

class Axes:
pass


be an option?

Importing classes just for typing in python? has no selected answers. This question is not about circular imports. It's about types from optional dependencies. Is there any other (newer) way than a type annotation in enclosed quotes like suggested in Importing classes just for typing in python??

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