what is the difference between super(type, obj) and super(type, type)

Question

class Person:
    def __init__(self, name):
        self.name = name
    # Getter function
    @property
    def name(self):
        return self._name
    # Setter function
    @name.setter
    def name(self, value):       
        if not isinstance(value, str):
            raise TypeError('Expected a string')
        print(self)
        self._name = value
    # Deleter function
    @name.deleter
    def name(self):
        raise AttributeError("Can't delete attribute")

class SubPerson(Person):
    @property
    def name(self):
        print('Getting name')
        return super().name
    @name.setter
    def name(self, value):
        print('Setting name to', value)
        super(SubPerson, SubPerson).name.__set__(self, value)
    @name.deleter
    def name(self):
        print('Deleting name')
        super(SubPerson, SubPerson).name.__delete__(self)

s = SubPerson('Guido')
print(s.name)

when i make the super(SubPerson, SubPerson).name.__set__(self, value) to
super(SubPerson, self).name.__set__(self, value) , i get this issue

AttributeError: 'SubPerson' object has no attribute '_name'

Why?

Answer 1

super(SubPerson, SubPerson) is a proxy to access overridden attributes of SubPerson , but super(SubPerson, self) is a proxy to access overridden attributes of self . By this, I mean that while it searches through class dicts for attribute lookup, it performs descriptor handling for instance attributes rather than class attributes.

super(SubPerson, self).name finds the name property in Person.__dict__ . It then calls __get__ automatically. The getter tries to read self._name , which doesn't exist, hence your error.