How does passing a lambda function for a property() work when extending Django's user model?

Question

I have been looking at extending the Django user model, and while I am confident I can make it work, there is a line of code that I really want to understand.

I have been referencing the following tutorial: http://blog.tivix.com/2012/01/06/extending-user-model-in-django/

but I can not for the life of me understand how the following line of code works:

User.profile = property(lambda u: u.get_profile() )

If I understand correctly, this sets the getter method for User.profile to an anonymous function that takes a user as an argument and returns the profile, BUT, if I am referencing myuser.profile, when is the argument actually passed?

I hope I communicated myself properly. Any help understanding this would be greatly appreciated!

Answer 1

It'd probably make more sense they wrote it this way

User.profile = property(lambda self: self.get_profile())

Or more verbosely:

class UserProfile(models.Model):  
    user = models.OneToOneField(User)  

    @property
    def profile(self):
        return self.get_profile()

    def __str__(self):  
          return "%s's profile" % self.user

The first argument of every instance method of a Python object is the instance of the class to which the method belongs. self is just a convention, so u works just as well.