python - Why should classes with __get__ or __set__ know who uses them? -

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I've just read it and it has been unknowingly felt that depending on who's class behavior it uses Could.

  • __ set __ (self, example, value)
    • go __ (self, example, owner)

      Do it the same way. They get in the example of the class that uses them. What is the reason for this design decision? How is this used?

      Update: I think about the descriptors in general form. Classes that use them as member types can easily be manipulated with the descriptors' side effects. Here's an example of what I mean, why does Python supprt? 

        class age (object): def __init __ (value): self.value = value def __get __ (self, example, owener): instance.name = 'manipulation you received' return self .value class person (object): age = age (42) name = 'peter' peter = person () print (peter name, 'is', peter .g)    
       
       
        __ go __  and  __ set __  about someone who calls them Do not get information. 3 Logic is the narrator object, the object being used, and the type of object.  
       I think the best way to clean it is with an example, so here's one:  
        class squares: def descriptor (self): return foo_instance = Foo () method_object = foo_instance.descriptor   
       Work Descriptions When you use the method of the object, apply the method object method and  __ get __  The caller is created by finding the function. Here  
        method_object = foo_instance.descriptor   
       call  descriptor .__ get __ (foo_instance, Foo)  to create  Method_object . The  __ go __  method does not receive any information about the caller, only necessary information for attribution access to do its job.

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