eight_digit_dates.py

from datetime import date, timedelta

def eight_digit_date(d: str):
    return all([str(x) in d for x in range(8)])

valid_dates = []
d = date(year=2000, day=1, month=1)
while d.year < 2100:
    if eight_digit_date(d.isoformat()): valid_dates.append(d)
    d += timedelta(days=1)
    
print(len(valid_dates))