code: def authorization_url(self, **kwargs):
          
          kwargs.setdefault('access_type', 'offline')
          url, state = self.oauth2session.authorization_url(
              self.client_config['auth_uri'], **kwargs)
  
          return url, state
docs: Generates an authorization URL.
  
          This is the first step in the OAuth 2.0 Authorization Flow. The user's
          browser should be redirected to the returned URL.
  
          This method calls
          :meth:`requests_oauthlib.OAuth2Session.authorization_url`
          and specifies the client configuration's authorization URI (usually
          Google's authorization server) and specifies that "offline" access is
          desired. This is required in order to obtain a refresh token.
  
          Args:
              kwargs: Additional arguments passed through to
                  :meth:`requests_oauthlib.OAuth2Session.authorization_url`
  
          Returns:
              Tuple[str, str]: The generated authorization URL and state. The
                  user must visit the URL to complete the flow. The state is used
                  when completing the flow to verify that the request originated
                  from your application. If your application is using a different
                  :class:`Flow` instance to obtain the token, you will need to
                  specify the ``state`` when constructing the :class:`Flow`.