parameters: (self, http_request)
docstring: Refreshes the access_token.
  
      This method first checks by reading the Storage object if available.
      If a refresh is still needed, it holds the Storage lock until the
      refresh is completed.
  
      Args:
        http_request: callable, a callable that matches the method signature of
          httplib2.Http.request, used to make the refresh request.
  
      Raises:
        AccessTokenRefreshError: When the refresh fails.
docstring_summary: Refreshes the access_token.
docstring_tokens: Refreshes the access_token .
function: def _refresh(self, http_request):
      """Refreshes the access_token.
  
      This method first checks by reading the Storage object if available.
      If a refresh is still needed, it holds the Storage lock until the
      refresh is completed.
  
      Args:
        http_request: callable, a callable that matches the method signature of
          httplib2.Http.request, used to make the refresh request.
  
      Raises:
        AccessTokenRefreshError: When the refresh fails.
      """
      if not self.store:
        self._do_refresh_request(http_request)
      else:
        self.store.acquire_lock()
        try:
          new_cred = self.store.locked_get()
          if (new_cred and not new_cred.invalid and
              new_cred.access_token != self.access_token):
            logger.info('Updated access_token read from Storage')
            self._updateFromCredential(new_cred)
          else:
            self._do_refresh_request(http_request)
        finally:
          self.store.release_lock()
function_tokens: def _refresh ( self , http_request ) : if not self . store : self . _do_refresh_request ( http_request ) else : self . store . acquire_lock ( ) try : new_cred = self . store . locked_get ( ) if ( new_cred and not new_cred . invalid and new_cred . access_token != self . access_token ) : logger . info ( 'Updated access_token read from Storage' ) self . _updateFromCredential ( new_cred ) else : self . _do_refresh_request ( http_request ) finally : self . store . release_lock ( )