code: def clean(self):
          '''Auto populate urlhash from url'''
          if not self.urlhash or 'url' in self._get_changed_fields():
              self.urlhash = hash_url(self.url)
          super(Reuse, self).clean(f clean(self):
          '''Auto populate urlhash from url'''
          if not self.urlhash or 'url' in self._get_changed_fields():
              self.urlhash = hash_url(self.url)
          super(Reuse, self).clean()
docs: Auto populate urlhash from url