def weekday_to_str(num):
    """
        Translate weekday to string
    """
    data = {
        '0': 'mon',
        '1': 'tue',
        '2': 'wed',
        '3': 'thu',
        '4': 'fri',
        '5': 'sat',
        '6': 'sun',
    }

    return data.get(str(num))