code: def _refresh(self):
          
          # Request and set a new API token.
          new_token = self.authenticate(self._username, self._password)
          self._token = new_token
          logger.info('New API token received: "{}".'.format(new_token))
          return self._token
docs: Refresh the API token using the currently bound credentials.
  
          This is simply a convenience method to be invoked automatically if authentication fails
          during normal client use.