optimizing django code model - django

Question

I want to optimizing this code. I think the best solution is to use the method pre_save and not override the save method. This is the function that delete the old image when in editing it upload new image
def delete_old_image(sender, instance):
try:
obj = sender.objects.get(id=instance.id)
except sender.DoesNotExist:
pass
else:
if not obj.image == instance.image:
try:
os.remove(obj.image.path)
except:
pass
under the code of the model
class Service(models.Model):
title= models.CharField(max_length=170)
slug = models.SlugField(max_length=200, blank=True, unique=True, editable=False)
def save(self, *args, **kwargs):
self.slug = slugify(self.title)
super(Service, self).save(*args, **kwargs)
class Portfoglio(models.Model):
title= models.CharField(max_length=170, unique=True)
slug = models.SlugField(max_length=200, blank=True, unique=True, editable=False)
image=models.ImageField(upload_to = 'images/' , default= 'images/foto.jpg', verbose_name='upload')
def save(self, *args, **kwargs):
self.slug = slugify(self.title)
if self.id is not None:
delete_old_image(Portfoglio, self)
super(Portfoglio, self).save(*args, **kwargs)
class Image(models.Model):
title= models.CharField(max_length=200)
image=models.ImageField(upload_to = 'images/' , default= 'images/foto.jpg', verbose_name='upload')
def save(self, *args, **kwargs):
if self.id is not None:
delete_old_image(Portfoglio, self)
super(Image, self).save(*args, **kwargs)
class Team(models.Model):
name= models.CharField(max_length=200)
image= models.ImageField(upload_to = 'images/' , default= 'images/foto.jpg', verbose_name='upload')
def save(self, *args, **kwargs):
if self.id is not None:
delete_old_image(Team, self)
super(Team, self).save(*args, **kwargs)

Answer 1

from django.db.models.signals import pre_save
from django.dispatch import receiver
#receiver(pre_save)
def pre_delete_old_image(sender, instance, created, **kwargs):
if sender not in [Service, Portfoglio, Image, Team]:
return
if getattr(sender, 'slug', False):
instance.slug = slugify(instance.title)
if not created and getattr(sender, 'image', False):
delete_old_image(sender, instance)
def delete_old_image(sender, instance):
try:
obj = sender.objects.get(id=instance.id)
except sender.DoesNotExist:
pass
else:
if obj.image != instance.image:
try:
os.remove(obj.image.path)
except Exception as e:
pass