Days in lieu when holiday falls on weekend

[andydoc]

I am a sloppy coder, sorry! Self-taught and a horrible mix between OOP and not.
I needed to do two things...

1. Use a subset of holidays - specifically of German holidays - inorder to use only holidays observed by a particular institution; and
2. Fix the failure to report a Monday (and maybe Tuesday at Xmas) as a non-work day when a holiday falls at the weekend.

I haven't time to contribute formally to the project, but here is my code which perhaps others may craft into something more formally acceptable:

from datetime import date, timedelta, datetime
from workalendar.europe import Germany

dif = timedelta(days = +1)

def holdate(datetocheck, filteredhols):
  for hol in filteredhols:
    if hol[0] == datetocheck:
      return True
  return False

def day_in_lieu(datetocheck):
  hols = cal.holidays(datetocheck.year)
  filteredhols = [hol for hol in hols if hol[1] in observedhols ]
  if (datetocheck.weekday() == 0 and (holdate(datetocheck-dif, filteredhols) or holdate(datetocheck-(2*dif),filteredhols))) or (datetocheck.weekday() == 1 and holdate(datetocheck-(3*dif),filteredhols) and holdate(datetocheck-(2*dif),filteredhols)):
    return True
  return False

def mod_working_day(datetocheck,observedhols):
  if datetocheck.weekday() < 5 and not day_in_lieu(datetocheck):
    return True
  return False

example use:

observedhols = ['New year','Good Friday','Easter Monday','Labour Day','Christmas Day','Second Christmas Day']
cal = Germany()
mod_working_day(date(1999, 5, 3),observedhols) --> False
mod_working_day(date(1999, 12, 28),observedhols) --> False
mod_working_day(date(2023, 1, 2),observedhols) --> False