def overlappingDates(date_set1, date_set2):
    """
    date_set1: (tuple) a tuple with the start date and end date
    date_set2: (tuple) a tuple with the start date and end date
    """
    if date_set1[0] > date_set2[0]:
        start_date = date_set1[0]
    else:
        start_date = date_set2[0]
    if date_set1[-1] < date_set2[-1]:
        end_date = date_set1[-1]
    else:
        end_date = date_set2[-1]
    return start_date, end_date
