add a latest method to query the latest x events

src/mahjong_ranking/tests.py

@@ -54,7 +54,7 @@ class KyuDanTest(TestCase):
 
         for ranking in KyuDanRanking.objects.all():
             original = {a: getattr(ranking, a) for a in self.equal_attrs}
-            confirmed_hanchans = Hanchan.objects.confirmed_hanchans(
+            confirmed_hanchans = Hanchan.objects.confirmed(
                 user=ranking.user,
                 since=ranking.legacy_date
             )
@@ -86,7 +86,7 @@ class KyuDanTest(TestCase):
                 'dan_points': ranking.legacy_dan_points or 0,
                 'kyu_points': ranking.legacy_kyu_points or 0
             }
-            confirmed_hanchans = Hanchan.objects.confirmed_hanchans(
+            confirmed_hanchans = Hanchan.objects.confirmed(
                 user=ranking.user,
                 since=ranking.legacy_date
             )