docs: def get_objects_with_attribute(self, obj_type, attribute, value):
          """
          :param obj_type: requested object type.
          :param attribute: requested attribute.
          :param value: requested attribute value.
          :return: all children of the requested type that have the requested attribute == requested value.
          """
          return [o for o in self.get_objects_by_type(obj_type) if o.get_attribute(attribute) == value]