In order to avoid duplicating this code, you could use something like:

```
@receiver(post_delete):
def delete_report(sender, instance, **kwargs):
activity = None
user = None
event = None
if sender.__name__ 'Event':
activity = Activity.objects.get(name=EVENT_CREATION_ACTIVITY)
user = instance.owner
event = instance
if sender.__name__ == 'Attendance':
activity = Activity.objects.get(name=EVENT_ATTENDANCE_ACTIVITY)
user = instance.user
event = instance.event

if activity:
 delete_the_report_here()
```