不修改代码，让调用方法 替换到另外一个方法

# coding=utf-8
class SomeClass(object):

    def __init__(self):
        # 替换speck方法
        self.speak= self.new_speak

    def speak(self):
        return "hello world"

    def new_speak(self):
        return "new hello"

 

some = SomeClass()
print(some.speak())
# 运行结果 new hello