code: def _authorize_credentials(self):
          
          try:
              http = self.credentials.authorize(httplib2.Http())
              self.service = discovery.build("calendar", "v3", http=http)
              return True
          except ServerNotFoundError:
              return False
docs: Fetches an access/refresh token by authorizing OAuth 2.0 credentials.
  
          Returns: True, if the authorization was successful.
                   False, if a ServerNotFoundError is thrown.