Python Master 1 exam review, datetime

# It's not easy
# I remember one question.
# If 999-9-9 is Monday, what day is 2020-2-2? Sunday

import datetime

t1=datetime.date(999, 9, 9)

t2=datetime.date(2020, 2, 2)

print((t2-t1).days)     # 372693

aa=['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']

bb=(t2-t1).days%7

print(aa[bb])   # Sun