code: def state(self):
          
          return dict(
              (attr, getattr(self, attr))
              for attr in (
                  'consumer_key', 'consumer_secret', 'callback_uri',
                  'verified', 'oauth_token', 'oauth_token_secret',
                  'oauth_session_handle', 'oauth_expires_at',
                  'oauth_authorization_expires_at', 'scope'
              )
              if getattr(self, attr) is not None
          )
docs: Obtain the useful state of this credentials object so that
          we can reconstruct it independently.