Question

class SessionWizardView(WizardView):
    @classonlymethod
    def as_view(cls, *args, **kwargs):
        #...snipped..
        pass

class ParentWizard(SessionWizardView):
    @classonlymethod
    def as_view(cls, *args, **kwargs):
        return super(SessionWizardView, cls).as_view( ... )

class ChildWizard(ParentWizard):
    @classonlymethod
    def as_view(cls, *args, **kwargs):
        return super(SessionWizardView, cls).as_view( ... )

In ChildWizard, is it legal to pass in a grandparent class (SessionWizardView) into the first parameter of super ? pylint is vomiting this error message:

Method should have "self" as first argument

Bad first argument ‘SessionWizardView’ given to super class

Answer 1

The usual usage of super for classmethods is to put cls first and the name of the current class as the second argument:

class SessionWizardView(WizardView):
    @classonlymethod
    def as_view(cls, *args, **kwargs):
        #...snipped..
        pass

class ParentWizard(SessionWizardView):
    @classonlymethod
    def as_view(cls, *args, **kwargs):
        return super(cls, ParentWizard).as_view( ... )

class ChildWizard(ParentWizard):
    @classonlymethod
    def as_view(cls, *args, **kwargs):
        return super(cls, ChildWizard).as_view( ... )

If you build working code that passes tests, I wouldn’t worry to much about how pylint reports the naming of the first argument. pylint knows that a standard Python classmethod will use cls as the first argument, but it doesn’t know anything about classonlymethod which has the same pattern.

References:

• http://docs.python.org/library/functions.html#super
• http://blogs.gnome.org/jamesh/2005/06/23/overriding-class-methods-in-python/
• http://pylint-messages.wikidot.com/messages:c0202