After upgrade from Pycharm 2017.2.3 to Pycharm 2017.1.4 Pycharm\'s Debugger suggested to build cpython (or sth associated with it):
Pycharm 2017.2.3
Pycharm 2017.1.4
p
Goto pycharm -> Preferences -> Build,Execution and deployment -> Python debugger
Check box Collect run-time types information for code insight.
This solved issues for me.