Why python metaclass is not working in this code?

Question

class My_meta(type):

    def hello(cls):
        print("hey")

class Just_a_class(metaclass=My_meta):
    pass

a = Just_a_class()
a.hello()

Above code is giving:

AttributeError: 'Just_a_class' object has no attribute 'hello'

Please suggest the changes to make it work. Thanks.

A metaclass is not the same as a superclass. Instances don't inherit methods from a metaclass. — Barmar
– Barmar, Commented Sep 27, 2019 at 21:15
Why do you believe that an instance of Just_a_class will have that method? — juanpa.arrivillaga
– juanpa.arrivillaga, Commented Sep 27, 2019 at 22:36

Barmar · Accepted Answer · 2019-09-27 21:18:41Z

1

Methods in a metaclass are inherited by the class object, not class instances. You can call the function this way:

Just_a_class.hello()
// or
a = Just_a_class()
a.__class__.hello()

answered Sep 27, 2019 at 21:18

Barmar

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1 Comment

Thanks for helping!