python setattr function does not set

Question

I have a module and two classes which are called A and B. I would like to record some functions from duvisiopy.model_functions module into class B by using class A then return B. As you can see the output1, they are recorded and they are runnable.

#duvisiopy.model_functions

def compile(self,
            loss_function,
            optimizer):
    self.loss_function = loss_function
    self.optimizer = optimizer

import types
import duvisiopy.model_functions


class B():
    def __init__(self):
        self.b = "b"

class A():

    def __init__(self):
        self.a = "a"
    def __new__(self, cls):
        for attr_name in dir(duvisiopy.model_functions):

            if attr_name not in dir(cls) and not attr_name.startswith("_"):

                attr = getattr(duvisiopy.model_functions, attr_name)
                if not isinstance(attr, types.ModuleType):

                    attr = attr.__get__(duvisiopy.model_functions,
                                        duvisiopy.model_functions.__class__)
                    print(attr_name)

                    setattr(cls, attr_name, attr)
        return cls



b = B()

a = A(b)
a.compile("test1","test2")

for i in dir(a):

    if not a.starsith("_"):
        print(i)

output1 is

compile
evaluate
fit
progressbar

However, If I try to reach a.optimizer, it throws error

Traceback (most recent call last):
  File "<pyshell#54>", line 1, in <module>
    a.optimizer
AttributeError: 'B' object has no attribute 'optimizer'

What is the problem ?

UPDATE 1

if I set compile function to return self

#duvisiopy.model_functions

def compile(self,
            loss_function,
            optimizer):
    self.loss_function = loss_function
    self.optimizer = optimizer

    return self

c = a.compile("test1","test2")

it prints

'absolute_path\\duvisiopy\\model_functions.py'

and if I try to reach optimizer by c, it prints,

print(c.optimizer) #--> 'test2'