def METHOD_NAME(self, alias_key: str) -> str:
    """
    Adds alias to the dictionary of aliases under given key.
    :param alias_key: key of relation to generate alias for
    :type alias_key: str
    :return: generated alias
    :rtype: str
    """
    alias = get_table_alias()
    self._aliases_new[alias_key] = alias
    return alias