Input:

from typing import Union def test1_func(arg: Union[None, str, int]) -> None: return 

Resulting documentation:
def test1_func(arg: Union[ForwardRef(None), str, int]) ‑> None

Expected documentation:
def test1_func(arg: Union[None, str, int]) ‑> None

!pdoc --version
pdoc 0.10.0