code: def get_last_weekday_in_month(year, month, weekday):
          
          day = date(year, month, monthrange(year, month)[1])
          while True:
              if day.weekday() == weekday:
                  break
              day = day - timedelta(days=1)
          return day
docs: Get the last weekday in a given month. e.g:
  
          >>> # the last monday in Jan 2013
          >>> Calendar.get_last_weekday_in_month(2013, 1, MON)
          datetime.date(2013, 1, 28)