Django ImagedModel. Delete all linked images after model instance delete.

models.py

class ImagedModel(models.Model):
    class Meta:
        abstract = True

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        pre_delete.connect(self.pre_delete, self.__class__, dispatch_uid='%s_pre_delete' % str(self.__class__).lower())

    def save(self, *args, **kwargs):
        try:
            old = self.__class__._default_manager.get(pk=self.pk)

            for field in self._meta.get_fields():
                if isinstance(field, FileField):
                    old_field = getattr(old, field.name, None)
                    new_field = getattr(self, field.name, None)

                    if new_field != old_field and not self.__class__._default_manager.filter(**{'%s__exact' % field.name: old_field}).exclude(pk=old.pk):
                        old_field.delete(False)
        except self.__class__.DoesNotExist:
            pass
        except Exception as e:
            print('Save %s error: %s' % (self.__class__, e))
        finally:
            super(ImagedModel, self).save(*args, **kwargs)

    @staticmethod
    def pre_delete(instance, **kwargs):
        for field in instance._meta.get_fields():
            if isinstance(field, FileField):
                file = getattr(instance, field.name, None)
                if not instance.__class__._default_manager.filter(**{'%s__exact' % field.name: file}).exclude(pk=instance._get_pk_val()):
                    file.delete(False)