def how_many_days(month_number):
    """Returns the number of days in a month.
    WARNING: This function doesn't account for leap years!
    """
    days_in_month = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
    result = days_in_month[month_number - 1]
    return result