UserDict: " Unexpected keyword argument..." error

[pawelswiecki]

mypy==0.590

from collections import UserDict

class MyDict(UserDict):
    pass

m = MyDict(bob=1, frank=2)

print(m)  # {'bob': 1, 'frank': 2}

now:

$ mypy user_dict.py 
user_dict.py:8: error: Unexpected keyword argument "bob" for "MyDict"
user_dict.py:8: error: Unexpected keyword argument "frank" for "MyDict"

I think this is not a derisable behaviour.

Correct me if it's not a typeshed issue, but a mypy one. Also, I did check (here and in google) I did not find anything on this particular thing.