Before we dive into how you can delegate responsibility in Python, lets first talk about what it means to use inheritance for this purpose. Inheritance allows a class to inherit all of the properties and methods from another class. This is useful when you want to create a new type that builds on an existing one. For example, suppose you have a base class called Animal: This defines some basic functionality for animalsnamely, making noise and moving around.

Now lets say we wanted to define a subclass of this called Dog:
Here, we’ve added two new methods that are specific to dogs (bark() and fetch()). We can then create an instance of the Dog class just like any other object in Python: This is all well and good. But what if you dont want to inherit from another class? What if you have a situation where you need to delegate some responsibility to another object, but you dont necessarily want to subclass it? Thats where delegation comes into play.

Delegating Responsibility in Python: The Delegate Pattern
The delegate pattern is an object oriented design pattern that allows one object (the client) to effectively act as another object (the server). This can be useful when you want to decouple your code and make it more modular, or when you need to provide a facade for some functionality. In Python, the delegate pattern is often implemented using closuresa technique that allows you to create functions within other functions.

Heres an example:
Here, we’ve defined a class called Delegate that takes another object as its argument (the server). The constructor assigns this object to a private attribute called _server. Then the delegate methods simply call their corresponding counterparts on the server object. This is just one way of implementing delegation in Python using closures, but there are other ways too.

For example, you could use decorators or mixins instead. The key idea behind delegation is to separate concerns and make your code more flexible and reusable.