code: def cumulative_sum(self):
          
          from .. import extensions
          agg_op = "__builtin__cum_sum__"
          return SArray(_proxy = self.__proxy__.builtin_cumulative_aggregate(agg_op))
docs: Return the cumulative sum of the elements in the SArray.
  
          Returns an SArray where each element in the output corresponds to the
          sum of all the elements preceding and including it. The SArray is
          expected to be of numeric type (int, float), or a numeric vector type.
  
          Returns
          -------
          out : sarray[int, float, array.array]
  
          Notes
          -----
           - Missing values are ignored while performing the cumulative
             aggregate operation.
           - For SArray's of type array.array, all entries are expected to
             be of the same size.
  
          Examples
          --------
          >>> sa = SArray([1, 2, 3, 4, 5])
          >>> sa.cumulative_sum()
          dtype: int
          rows: 3
          [1, 3, 6, 10, 15]