code: def remove_child(self, router):
          '''remove a :class:`Router` from the :attr:`routes` list.'''
          if router in self.routes:
              self.routes.remove(router)
              router._parent = Nonf remove_child(self, router):
          '''remove a :class:`Router` from the :attr:`routes` list.'''
          if router in self.routes:
              self.routes.remove(router)
              router._parent = None
docs: remove a :class:`Router` from the :attr:`routes` list.