docs: def _sql_params(sql):
      """
      Identify `sql` as either SQL string or 2-tuple of SQL and params.
      Same format as supported by Django's RunSQL operation for sql/reverse_sql.
      """
      params = None
      if isinstance(sql, (list, tuple)):
          elements = len(sql)
          if elements == 2:
              sql, params = sql
          else:
              raise ValueError("Expected a 2-tuple but got %d" % elements)
      return sql, params