code: def _join(self, rows):
      '''
      Join multiple rows worth of data into a single result.
      '''
      rval = 0
      for row in rows:
        if row: rval += row
      return rvaf _join(self, rows):
      '''
      Join multiple rows worth of data into a single result.
      '''
      rval = 0
      for row in rows:
        if row: rval += row
      return rval
docs: Join multiple rows worth of data into a single result.