Unable to work with Stem and Tor

I want to work with Tor through the Stem module. Below is my code for connecting to Tor:

import sys
from stem.connection import connect

if __name__ == '__main__':
    controller = connect()

    if not controller:
        sys.exit(1)  # unable to get a connection

    print 'Tor is running version %s' % controller.get_version()
    controller.close()

      

        
        
        
      

    

However, when running the code, I get the following error: Unable to connect to tor. Are you sure it works?

I turned on Tor and checked the code again and nothing happened. The problem is this line:

if __name__ == '__main__':
    controller = connect()

      

        
        
        
      

    

Even if I enter the connect () method into the Python interpreter, I get an error. What is the error and how can I fix it?