Implementing bound method using descriptor

Question

My question is related to bound method object, more specifically I am trying to imitate the same behavior that functions (which are essentially descriptors) present.

Let me first put here my understanding of how class_instance.function() works

Class D(object):
    def dfunc(self):
        ...

d=D()
d.dfunc() # will call D.__dict__['dfunc'].__get__(d,D)()

#gives a bound method which can be used directly
a=D.__dict__['dfunc'].__get__(d,D) 
a() #works as d.D()

Does Python call D.__dict__['dfunc'] (d), in case when type(dfunc) is function and type(d).__dict__['dfunc'].__get__(d, type(d)) if x is a class instance?

Now coming to how I am trying to create a bound object using closure:

class E(object):
    def __get__(self,obj,cls):

        def returned(*args):
            print(obj.__dict__)
        return returned

class F(object):
    e=E()
    y=9

f=F()
f.fvar=9 #putting something in instances __dict__
a=f.e #will call the __get__ function of F and return a closure
a() #works and produces instance specific result -> {'fvar': 9}, just like a bound method

Now the main question, when I did a=D.__dict__['dfunc'].__get__(d,D) type(a) was bound method, but when I implement it type(a) is function; is there a way to return bound object from user-defined descriptor?

Is there any better way to implement a function like descriptor? Please correct me if I have gotten something fundamentally incorrect in my head.

Answer 1

If you want to return a method instead, you can create one from the function object together with the arguments passed to __get__:

import types

class E(object):
    def __get__(self,obj,cls):

        def returned(*args):
            print(obj.__dict__)
        return types.MethodType(returned, obj, cls)

However, it's not totally clear what this gains you. If just returning a function already works, why do you need it to be a "real" method?