class A:
def print(self):
print("A.print")
class B(A):
def print(self):
print("B.print")
class C(A):
def print(self):
print("C.print")
class D(B, C):
pass
d = D()
d.print() #"B.print", but if you change the order of base classes in D, it will yield "C.print"