Unresolved attribute reference 'keys' for class 'dict'
I've had this bug in PyCharm 2019.3 too. The problem was that the virtualenv I used was not excluded.
More details: https://youtrack.jetbrains.com/issue/PY-34943
As per user2235698's comment above and based on my verification, this is because of a buggy pycharm version. Please update your pycharm.