super() in Python 3
Thanks for your explanation. But I tried your code and it doesn't work
File "<...>\site-packages\django\test\runner.py", line 600, in run_tests
suite = self.build_suite(test_labels, extra_tests)
File "<...>\speedy\core\base\test\models.py", line 35, in build_suite
return super().build_suite(test_labels=test_labels, *args, **kwargs)
TypeError: build_suite() got multiple values for argument 'test_labels'
uri at speedy.net
On Tue, Jul 16, 2019 at 3:13 PM Rhodri James <rhodri at kynesim.co.uk> wrote:
> Hi there! A lot of the answers to your questions are at least implied
> in the Fine Manual
> (https://docs.python.org/3/library/functions.html#super), but it's not
> very clear and written more for precision than comprehension. Here's my
> attempt at explaining :-)
> On 16/07/2019 11:08, ???? wrote:
> > Hi,
> > 1. When we use super() in Python 3, we don't pass it the first argument
> > (self). Why?
> Actually the first argument to super() isn't self, it's the class that
> we want the superclass of. The *second* argument is self. In the
> normal course of using super() inside a class method, these arguments
> will almost always be the class itself and the instance the method was
> called on. Since that's almost always the case, the compiler offers us
> a short-cut: omit the "cls" and "self" and the compiler will fill them
> in for us. That way we don't have to repeat ourselves and risk
> mis-typing something.
> > What happens if the first argument is not self?
> The first argument of what? I'm not sure what you're getting at here.
> > I think it would make more sense to use something like
> > self.super().__init__(*args, **kwargs) or something like this.
> That would mean either forbidding classes to have a method named "super"
> or accepting that users' classes could completely screw up inheritance
> for their subclasses.
> > 2. I want to override a function called build_suite in an inherited
> > The function receives an argument "test_labels" which I want to change (I
> > define it if it's not defined), but I don't do anything with the argument
> > "extra_tests". Is it possible to include "extra_tests" in *args, **kwargs
> > and how?
> Don't list it in your parameters :-)
> def build_suite(self, test_labels=None, *args, **kwargs):
> return super().build_suite(test_labels=test_labels, *args, **kwargs)
> > I think maybe they will release another version in the future
> > without "extra_tests", or with additional arguments, and I don't want to
> > have to change my code then.
> With a shim layer like this, your chances of getting away with making no
> changes to your code when an API you use changes are rather small.
> Rhodri James *-* Kynesim Ltd