There is an error in https://docs.python.org/3/library/stdtypes.html#types-union example.

Looks like there is no types.UnionType

BROKEN:

>>> import types
>>> isinstance(int | str, types.UnionType)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'types' has no attribute 'UnionType'. Did you mean: 'FunctionType'?
>>> [att for att in dir(types) if 'Union' in att]
['Union']
>>>

WORKING:

>>> import types
>>>
>>> isinstance(int | str, types.Union)
True
>>>

I'll raise a PR shortly.

Thanks for the PR Vivek. Can you please tell me the exact 3.10 version you're running? In earlier 3.10 versions (alpha, beta etc.) types.Union existed, but somewhere later (rc1,rc2) it became types.UnionType.

The final 3.10.0 release has types.UnionType, not types.Union. I suspect you might be running an earlier iteration of 3.10.

Thanks Ken. 

You are right I'm using 3.10.0b4. I just tested it on 3.10.0 and it works fine.

>>> import types
>>> isinstance(int | str, types.UnionType)
True