_Friday 13th or Black Friday is considered as unlucky day. Calculate how many unlucky days are in the given year._
Find the number of Friday 13th in the given year.
__Input:__ Year as an integer.
__Output:__ Number of Black Fridays in the year as an integer.
__Examples:__
        unluckyDays(2015) == 3
        unluckyDays(1986) == 1
***Note:*** In Ruby years will start from 1593.
from datetime import datetime
def unlucky_days(year: int) -> sum:
    return sum(datetime(year, month, 13).weekday() == 4 for month in range(1, 13))
from datetime import datetime
def unlucky_days(year: int) -> sum:
    return sum(datetime(year, month, 13).weekday() == 4 for month in range(1, 13))