Python class self variable as default when no argument given error

Question

I am writing a class in Python3 and want a method to take a default self variable when no explicit value is given. For some reason this doesn't seem to work.

For example, the following code would produce a NameError: name 'self' is not defined error for the 5th line.

class A:
    def __init__(self, a):
        self.a = a

    def func(self, b=self.a):
        pass

Is there a way around this if I want to make my function behave in the manner I specified?

Answer 1

This might be what you want.

If func is invoked without a parameter then b would be set to the value of self.a.

class A:
    def __init__(self, a):
        self.a = a

    def func(self, b=None):
        if not b:
            b = self.a
        pass