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lists/models.py (ch18l025).
@property
def
name
(
self
):
return
self
.
item_set
.
first
()
.
text
The @property Decorator in Python
If you haven’t seen it before, the
@property
decorator transforms a method on a class
to make it appear to the outside world like an attribute.
This is a powerful feature of the language, because it makes it easy to implement “duck
typing”, to change the implementation of a property without changing the interface of
the class. In other words, if we decide to change
.name
into being a “real” attribute on
the model, which is stored as text in the database, then we will be able to do so entirely
transparently—as far as the rest of our code is concerned, they will still be able to just
access
.name
and get the list name, without needing to know about the implementation.
Of course, in the Django template language,
.name
would still call the method even if it
didn’t have
@property
, but that’s a particularity of Django, and doesn’t apply to Python
in general…
And that, believe it or not, actually gets us a passing test, and a working “My Lists” page
( Figure 18-1)!
Figure 18-1. The “My Lists” page, in all its glory (and proof I did test on Windows)
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Chapter 18: Finishing “My Lists”: Outside-In TDD