def get_last_month(month, year):
    """
    Get last month of given month and year
    :param month: given month
    :param year: given year
    :return: last month and it's year
    """
    if month == 1:
        last_month = 12
        last_year = year - 1
    else:
        last_month = month - 1
        last_year = year
    return last_month, last_year