code: def _take_values(self, item: Node) -> DictBasicType:
          
  
          values = super()._take_values(item)
          values['_parent'] = None
          return values
docs: Takes snapshot of the object and replaces _parent property value on None to avoid
          infitinite recursion in GPflow tree traversing.
  
          :param item: GPflow node object.
          :return: dictionary snapshot of the node object.