code: def get_as_nullable_map(self, key):
          
          value = self.get_as_object(key)
          return AnyValueMap.from_value(value)
docs: Converts map element into an AnyValueMap or returns None if conversion is not possible.
  
          :param key: a key of element to get.
  
          :return: AnyValueMap value of the element or None if conversion is not supported.