docs: def get_objects_by_type_in_subtree(self, *types):
          """
          :param types: requested object types.
          :return: all children of the specified types.
          """
  
          typed_objects = self.get_objects_by_type(*types)
          for child in self.objects.values():
              typed_objects += child.get_objects_by_type_in_subtree(*types)
          return typed_objects