Member is not assignable error when accessing a module member #5439

Hi,

This issue seems close to the one that was fixed in this PR.

• Are you reporting a bug, or opening a feature request?

I'm reporting a bug.

• Please insert below the code you are checking with mypy,
  or a mock-up repro if the source is private. We would appreciate
  if you try to simplify your case to a minimal repro.

import functools

class Foo:
    bar = functools

foo = Foo()
foo.bar  # error: Member "bar" is not assignable

• What is the actual behavior/output?

test.py:7: error: Member "bar" is not assignable

• What is the behavior/output you expect?

No Error. I'm just accessing, not mutating.

• What are the versions of mypy and Python you are using?
  Do you see the same issue after installing mypy from Git master?

$ mypy --version
mypy 0.620

Same error on master.

• What are the mypy flags you are using? (For example --strict-optional)

No flags. Just raw mypy test.py

If you need any further information, please let me know.
Thank you in advance.