code: def add_callbacks(self, callback, errback,
                        callback_args=(), callback_kwargs=None,
                        errback_args=(), errback_kwargs=None):
          
          self.add_callback(callback, *callback_args, **(callback_kwargs or {}))
          self.add_errback(errback, *errback_args, **(errback_kwargs or {}))
docs: A convenient combination of :meth:`.add_callback()` and
          :meth:`.add_errback()`.
  
          Example usage::
  
              >>> session = cluster.connect()
              >>> query = "SELECT * FROM mycf"
              >>> future = session.execute_async(query)
  
              >>> def log_results(results, level='debug'):
              ...     for row in results:
              ...         log.log(level, "Result: %s", row)
  
              >>> def log_error(exc, query):
              ...     log.error("Query '%s' failed: %s", query, exc)
  
              >>> future.add_callbacks(
              ...     callback=log_results, callback_kwargs={'level': 'info'},
              ...     errback=log_error, errback_args=(query,))