[python] NameError: name 'self' is not defined

Why such structure

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

    def p(self, b=self.a):
        print b

gives an error NameError: name 'self' is not defined?

If you have arrived here via google, please make sure to check that you have given self as the first parameter to a class function. Especially if you try to reference values for that object instance inside the class function.

def foo():
    print(self.bar)

>NameError: name 'self' is not defined

def foo(self):
    print(self.bar)

For cases where you also wish to have the option of setting 'b' to None:

def p(self, **kwargs):
    b = kwargs.get('b', self.a)
    print b