How to prevent PyCharm from reformatting my code

I am trying to follow PEP8 which suggests spaces around operators should follow precedence. Therefore I do not want PyCharm to reformat them. I have:
Editor -> General -> Smart Keys -> Reformat on paste = None

Editor -> Code Style -> Python -> Spaces -> Additive operators = False

Editor -> Code Style -> Python -> Spaces -> Multiplicative operators = False

but still when i paste, PyCharm will remove spaces.
E.g. "2*2 + 4" will be formatted to "2*2+4"
or "(2+2) * 4" will be formatted to "(2+2)*4"

How can I force PyCharm to respect my mixed style and not change spacing at all around operators?
Is my best option to map Ctrl-V to "paste as plain"?