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.

def get_as_nullable_map(self, key):
        """
        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.
        """
        value = self.get_as_object(key)
        return AnyValueMap.from_value(value)