code: def _separate_objects_by_boxes(self, objects: Set[Object]) -> Dict[Box, List[Object]]:
          
          objects_per_box: Dict[Box, List[Object]] = defaultdict(list)
          for box in self.boxes:
              for object_ in objects:
                  if object_ in box.objects:
                      objects_per_box[box].append(object_)
          return objects_per_box
docs: Given a set of objects, separate them by the boxes they belong to and return a dict.