생성자에서 옵션받기

new.py

class A(object):

    def __new__(cls, version=0):
        if version==0:
            return super(A, cls).__new__(cls)
        elif version==1:
            return A1.__new__(A1)

    def whoami(self):
        print("A")

class A1(A):

    def whoami(self):
        print("A1")

a = A()
a.whoami()

a1 = A(version=1)
a1.whoami()