BIG UPD: migrate to python 3.10 and django 3.2

dav_events/models/trash/trashed_participant.py

@@ -1,15 +1,13 @@
 # -*- coding: utf-8 -*-
 from __future__ import unicode_literals
 from django.db import models
-from django.utils.encoding import python_2_unicode_compatible
 from django.utils.translation import ugettext_lazy as _
 
 from ..participant import AbstractParticipant
 
 
-@python_2_unicode_compatible
 class TrashedParticipant(AbstractParticipant):
-    event = models.ForeignKey('Event', related_name='trashed_participants')
+    event = models.ForeignKey('Event', related_name='trashed_participants', on_delete=models.CASCADE)
     created_at = models.DateTimeField()
     trashed_at = models.DateTimeField(auto_now_add=True)
     position = models.IntegerField(verbose_name='Listennummer')