old_contents: from django.db.models.signals import post_save
  from django.dispatch import receiver
  
  from applications import models
  
  
  # Delete DraftApplication when application submitted
  @receiver(post_save, sender=models.Application)
  def clean_draftapplication(sender, instance, created, *args, **kwargs):
      if not created:
          return None
      # Delete draft as its no longer needed
      models.DraftApplication.objects.filter(user=instance.user).delete()
  
new_contents: from django.db.models.signals import post_save
  from django.dispatch import receiver
  
  from applications import models
  
  
  # Delete DraftApplication when application submitted
  @receiver(post_save, sender=models.Application)
  def clean_draft_application(sender, instance, created, *args, **kwargs):
      if not created:
          return None
      # Delete draft as its no longer needed
      models.DraftApplication.objects.filter(user=instance.user).delete()
  
subject: Update applications/signals.py