code: def agg(self, aggregations):
          
          check_type(aggregations, list)
  
          new_index = Index(np.array(aggregations, dtype=np.bytes_), np.dtype(np.bytes_))
  
          return _series_agg(self, aggregations, new_index)
docs: Multiple aggregations optimized.
  
          Parameters
          ----------
          aggregations : list of str
              Which aggregations to perform.
  
          Returns
          -------
          Series
              Series with resulting aggregations.