@classmethod
def get_alias(cls, index_name=None):
    """Get the index alias as list."""
    conn = cls.get_connection()
    if not index_name:
        index_name = cls.get_index_name()
    alias_list = conn.indices.get_alias(index_name)
    return list(alias_list[cls.get_index_name()]['aliases'].keys())
