def get_bbox_str(bbox):
  """Build bounding box string as left_top_right_bottom_score

  :param bbox: dictionary with keys: ``left``, ``top``, ``right``, ``bottom``, ``score``
  :type bbox: dict
  :return: bounding box string
  :rtype: string
  """
  #
  return "_".join(["{}"]*5).format(bbox["left"], bbox["top"], bbox["right"], bbox["bottom"],
                                   bbox["score"])