How to create a unique slug in Django

Question

I am trying to create a unique slug in Django so that I can access a post via a url like this: http://www.example.com/buy-a-new-bike_Boston-MA-02111_2

The relevant m

Answer 1

class Need(models.Model):
    title = models.CharField(max_length=50)
    us_zip = models.CharField(max_length=5)
    slug = models.SlugField(unique=True)

    def save(self, **kwargs):
        slug_str = "%s %s" % (self.title, self.us_zip) 
        super(Need, self).save()