What is a mixin and why is it useful?

A mixin in Python is a class that is used to add specific functionality to other classes without inheriting from them. Mixins are useful because they allow for more flexible and modular code by allowing multiple classes to share functionality without inheriting from a common base class.

Here is an example of a simple mixin class in Python:

class LoggingMixin:
    def log(self, message):
        print(f"Log: {message}")

class MyClass(LoggingMixin):
    def do_something(self):
        self.log("Doing something...")

my_object = MyClass()
my_object.do_something()

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In this example, the LoggingMixin class provides a log method that can be used to print out messages. The MyClass class then inherits from this mixin class, allowing it to use the log method without having to define it itself. This allows the MyClass class to focus on its own specific functionality, while still being able to use the logging functionality provided by the mixin.