def _find_one_after_last_labeled_index(self):
        body_index = 0
        while self.bodies[body_index].segment_id in self.state.body_labels:
            body_index += 1
        return body_index
def _acc_grads(g_sum, g_w, g):
  """Accumulate gradients in g, weighted by g_w."""
  return [g_sum_i + g_w * g_i for g_sum_i, g_i in zip(g_sum, g)]