mro

class A:
    def __init__(self):
        print('A_init')
        
    def greeting(self):
        print('안녕하세요. A입니다.')
class B(A):
    def __init__(self):
        super().__init__()
        print('B_init')
        
    def greeting(self):
        print('안녕하세요. B입니다.')

class C(A):
    def __init__(self):
        super().__init__()
        print('C_init')
    
    def greeting(self):
        print('안녕하세요. C입니다.')

class D(B, C):
    def __init__(self):
        super().__init__()
        print('D_init')
    
    pass

x = D()
x.greeting()    # 안녕하세요. B입니다.

print(D.mro())