<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def _ssweek_of_month(date_value):
    "0-starting index which Sundaystarting-week in the month this date is"
    weekday_of_first = (date_value.replace(day=1).weekday() + 1) % 7
    return (date_value.day + weekday_of_first - 1) // 7