python inheritance share variable

inheritance_demo.py

class Parent():
    i = 123

    def assign(self, n):
        self.i = n


class ChildA(Parent):
    def f1(self):
        Parent.assign(self, 1)
        print("self:", self.i)

    def f2(self):
        print("self:", self.i)


class ChildB(Parent):
    def f1(self):
        Parent.assign(self, 2)
        print("self:", self.i)


ChildA = ChildA()
ChildA.f2()
ChildA.f1()
ChildB = ChildB()
ChildB.f1()
ChildA.f2()
print(ChildA.i)

# RESULT:
# self: 123
# self: 1
# self: 2
# self: 1
# 1