I have the following model containing a `FileField` where the user provide a zip file containing pictures. This zip file is precessed by a method called `process_zipfile()` during the save. 

```
class Album(models.Model):
   nom = models.CharField(max_length = 200)
   added_by = models.ForeignKey(User, null=True, blank=True)
   gallery = models.ForeignKey(Gallery, null=True, blank=True)
   zip_file = models.FileField('image field .zip', upload_to=PHOTOLOGUE_DIR+"/temp",
                 help_text='Select a .zip file of images to upload into a new Gallery.')

   class Meta:
       ordering = ['nom']

   def save(self, *args, **kwargs):
      self.gallery = self.process_zipfile()
      super(Album, self).save(*args, **kwargs)

   def delete(self, *args, **kwargs):
      photos = self.gallery.photos.all()
      for photo in photos:
            photo.delete()
      self.gallery.delete()
      super(Album, self).delete(*args, **kwargs)

   def process_zipfile(self):
      if os.path.isfile(self.zip_file.path):
      ......(creates gallery object and links the photos)
      return gallery

```

it works ok except that the field `gallery` (left blank by the form) is not populated by the gallery created by `process_zipfile()`. What am I doinfg wrong?

Besides, the delete method doesn't seem to work, any idea?