code: def create_deeper(self,
                        new_t1,
                        new_t2,
                        child_relationship_class,
                        child_relationship_param=None,
                        report_type=None):
          
          level = self.all_down
          result = DiffLevel(
              new_t1, new_t2, down=None, up=level, report_type=report_type)
          level.down = result
          level.auto_generate_child_rel(
              klass=child_relationship_class, param=child_relationship_param)
          return result
docs: Start a new comparison level and correctly link it to this one.
          :rtype: DiffLevel
          :return: New level