def append_id(expr, id_col='append_id'):
    """
    Append an ID column to current column to form a new DataFrame.

    :param str id_col: name of appended ID field.

    :return: DataFrame with ID field
    :rtype: DataFrame
    """
    if hasattr(expr, '_xflow_append_id'):
        return expr._xflow_append_id(id_col)
    else:
        return _append_id(expr, id_col)
def append_id ( expr , id_col = 'append_id' ) : if hasattr ( expr , '_xflow_append_id' ) : return expr . _xflow_append_id ( id_col ) else : return _append_id ( expr , id_col )
Append an ID column to current column to form a new DataFrame.

    :param str id_col: name of appended ID field.

    :return: DataFrame with ID field
    :rtype: DataFrame