Python 请问有没有可能从一个类的方法到另一个类的方法再回到第一个类的同一个方法？

Question

测试代码如下，运行会有错误。
请问怎么写才能实现从Admin.start()到Config.middle()再回到Admin.start()呢？

class Admin:

    def __init__(self, config):
        self.config = config

    def start(self):
        print('start')
        return self.config.middle()


class Config:

    def __init__(self, base_dir):
        self.base_dir = base_dir

    def middle(self):
        print('middle')
        return Admin.start(self)

def main():
    config = Config(r'C:\Users\niko\Desktop\QA\test')
    admin = Admin(config)
    admin.start()

if __name__ == "__main__":
    main()

------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-53-67a4e287e160> in <module>
     26 
     27 if __name__ == "__main__":
---> 28     main()

<ipython-input-53-67a4e287e160> in main()
     23     config = Config(r'C:\Users\peiran.peng\Desktop\QA\第三讲\test')
     24     admin = Admin(config)
---> 25     admin.start()
     26 
     27 if __name__ == "__main__":

<ipython-input-53-67a4e287e160> in start(self)
      6     def start(self):
      7         print('start')
----> 8         return self.config.middle()
      9 
     10     def end(self):

<ipython-input-53-67a4e287e160> in middle(self)
     18     def middle(self):
     19         print('middle')
---> 20         return Admin.start(self)
     21 
     22 def main():

<ipython-input-53-67a4e287e160> in start(self)
      6     def start(self):
      7         print('start')
----> 8         return self.config.middle()
      9 
     10     def end(self):

AttributeError: 'Config' object has no attribute 'config'

Answer 1

# -*- coding: UTF-8 -*-
class Admin:

    def __init__(self, config):
        self.config = config

    def start(self):
        print('start')
        self.config.middle(self)
        print('continue start')

class Config:

    def __init__(self, base_dir):
        self.base_dir = base_dir

    def middle(self, admin):
        print('middle')

def main():
    config = Config(r'C:\Users\niko\Desktop\QA\test')
    admin = Admin(config)
    admin.start()

if __name__ == "__main__":
    main()