Am using Python 3.6.5rcs , pip version 9.0.1 , selenium 3.11.0. The Python is installed in C:\Python and selenium is in C:\Python\Lib\site-packages\selenium. The environment variables have been set. 
But the code
from selenium import webdriver
gives an unresolved reference error.
Any suggestion on how to fix the problem.
I used this command to resolve my error.
pip install webdriver_manager
Pycharm Referenced Error With Import Selenium Webdriver