Python mixins with sample

Mixin is a way to create duck type in python . It could be useful for code reuse in some cases

Use case #1 A way for a “light-weight multi inheritance”

>>> class parent1:
...     def hello(self):
...         print('hello')
...
>>> class parent2:
...     def greeting(self):
...         print('hi')
...
>>> class child(parent1, parent2):
...     def hi(self):
...         self.hello()
...         self.greeting()
...
>>> c = child()
>>> c.hi()
hello
hi

when conflict ,the left most wins

>>> class Mixin1(object):
...     def test(self):
...         print ("Mixin1")
...
>>> class Mixin2(object):
...     def test(self):
...         print ("Mixin2")
...
>>> class MyClass(Mixin1, Mixin2):
...     pass
...
>>> MyClass().test()
Mixin1

Use case #2 wrapper, adapter or factory functions

define the models

>>> class user_model :
...     def __init__(self, name, email):
...         self.name = name
...         self.email = email
...     def __repr__(self):
...         return f'{self.name}, {self.email}'
...
>>> class customer_model:
...     def __init__(self, name, id):
...         self.name = name
...         self.id = id
...     def __repr__(self):
...         return f'{self.name}, {self.id}'
...

define a testing factory (also could be wrapper or helper)

>>>
>>> class model_factory:
...     def create_user(self, kwargs):
...         return user_model(**kwargs)
...     def create_customer(self, kwargs):
...         return customer_model(**kwargs)
...
>>>

a testing service

>>> class service(model_factory):
...     def test(self):
...         print(self.create_user({'name':'123','email':'test@gmail.com'}))
...         print(self.create_customer({'name':'456','id':1}))
...
>>> service().test()
123, test@gmail.com
456, 1

Mixin brings the code reusability from factory class or wrapper , adapter or converter .A mixin works as a kind of inheritance, but instead of defining an “is-a” relationship it may be more accurate to say that it defines an “includes-a” relationship

It has more focus on how “group” similar functions into classes then reuse by inheritance ;plus import and decorator which provides complete flexibility how to reuse code and get better structure.