sometimes it happen that a library is installed in more than one environment paths. By environment path i mean print(sys.path) in python, in this case it may happen that when you import the library you import only one path due to which some of the modules you won't get, to resolve this issue club all the folders in one. This issue may arise when you are installing a library from different commands like one from "apt get install python-google" and other from pip3 install google with above command you will get one folder in "/usr/local/lib/python3.6/dist-packages/google" and other in "/usr/lib/python3/dist-packages/google"