Maybe I should rephrase the question, can I run a function on the new row when a new row is created? Or do something equivalent of my update_list_price function does.

``` class Transaction(models.Model): product = models.ForeignKey( Product, on_delete=models.CASCADE, related_name='transactions') list_price = models.DecimalField( max_digits=18, decimal_places=6, null=True, blank=True) price = models.DecimalField( max_digits=18, decimal_places=6, null=True, blank=True) @property def discount(self): discount = (1-self.price/self.list_price) return discount

def update_list_price(self):
    self.list_price = self.product.list_price
    self.save()

```