code: def get_eids(self, num_rlzs):
          
          num_events = self.n_occ if self.samples > 1 else self.n_occ * num_rlzs
          return TWO32 * U64(self.serial) + numpy.arange(num_events, dtype=U64)
docs: :param num_rlzs: the number of realizations for the given group
          :returns: an array of event IDs