Question

Please point where a bug in my code.

class Foo:
    def get(self):
        return self.a

    def set(self, a):
        self.a = a

Foo.set(10)
Foo.get()

TypeError: set() takes exactly 2 positional arguments (1 given)

How to use __get__()/__set__()?

Answer 1

They are instance methods. You have to create an instance of Foo first:

f = Foo()
f.set(10)
f.get()    # Returns 10