def METHOD_NAME(cls):
    r"""Returns the available merging schemes
    Returns
    -------
    Iterator
        Iterator over the sample ids
    See Also
    --------
    keys
    """
    with qdb.sql_connection.TRN:
        sql = """SELECT archive_merging_scheme_id, archive_merging_scheme
                 FROM qiita.archive_merging_scheme"""
        qdb.sql_connection.TRN.add(sql)
        return dict(qdb.sql_connection.TRN.execute_fetchindex())