diff --git a/calendar/teachingdates/app.py b/calendar/teachingdates/app.py
index 4d448e2..924824d 100644
--- a/calendar/teachingdates/app.py
+++ b/calendar/teachingdates/app.py
@@ -22,7 +22,7 @@
                 prog=PROG, c=dates_config.get_period_config()))
             print("{prog}: debug: paper config: {c}".format(
                 prog=PROG, c=dates_config.get_paper_config()))
-        cal = calendars.TeachingCalendar.from_configuration(dates_config)
+        cal = calendars.TeachingCalendar(dates_config)
         if args.debug:
             print("Calendar: {cal}".format(cal=cal.calendar()))
             print("Lectures: {lec}".format(lec=cal.lecture_dates()))