In Python, a mixin is a class that is designed to add a specific behavior or set of behaviors to one or more other classes. It can provide a flexible way to add functionality to a class without modifying the class directly or making the inheritance relationship of subclasses complicated.

For example, we define a class ToDictMixin as follows:

Now, any other classes that need the converting to dictionary functionality can inherit this mixin class besides its original parent class:

class MyClass(ToDictMixin, BaseClass):

pass

Python allows multiple inheritances. This is why we can use mixins. But here is a frequently asked question:

Under multiple inheritances, if two parent classes have the same methods or attributes, what will happen?

In fact, if two parent classes have the same method or attribute, the method or attribute in the class that appears first in the inheritance list will take precedence. This means that if you try to access the method or attribute, the version from the first class in the inheritance list will be used.