code: def _comp_bbox(el, el2):
      
      # only compare if both elements have x/y coordinates
      if _comp_bbox_keys_required <= set(el.keys()) and \
              _comp_bbox_keys_required <= set(el2.keys()):
          if _box_in_box(el2, el):
              return 1
          if _box_in_box(el, el2):
              return -1
      return 0
docs: Return 1 if el in el2, -1 if el2 in el, else 0