def get_weekly_report_subject(week_day, person):
    """
    Returns subject string for weekly report email

    `week_day:datetime.date` - any date for the week we are reporting for
    `person:str` - reporting person's name, e.g. 'Jon Doe'
    """
    calendar_time = 'week {:02}'.format(week_day.isocalendar()[1])
    subject = 'Weekly report for {person} ({calendar_time})'.format(person=
        person, calendar_time=calendar_time)
    return subject
