NOTE: This library was born before there were better solutions that now exist. The library holidays is better maintained and more accurate and includes not only german holidays but many other countries as well. I would suggest you use it instead.
from german_holidays import get_german_holiday_calendar
# german holiday class for nordrhein-westfalen
cal_cls = get_german_holiday_calendar('NW')
cal = cal_cls()
print(cal.holidays())