The super() function in Python is a built-in that allows you to call methods from a parent class. It’s particularly useful in inheritance scenarios, enabling you to extend or override the functionality of inherited methods. Understanding how super() works is crucial for writing clean, maintainable, and robust object-oriented code.

This article will explore the intricacies of super(), including its behavior in single and multiple inheritance, and provide practical examples to illustrate its usage.

In single inheritance, a class inherits from only one parent class. The super() function simplifies calling methods from the parent class, especially the __init__() method (the constructor). This ensures that the parent class’s initialization logic is executed.

For example:

class Parent:
    def __init__(self, name):
        self.name = name

class Child(Parent):
    def __init__(self, name, age):
        super().__init__(name)
        self.age = age

In this example, super().__init__(name) in the Child class calls the __init__() method of the Parent class, ensuring that the name attribute is initialized correctly before the age attribute is set.

Multiple inheritance occurs when a class inherits from multiple parent classes. In this case, super() uses the method resolution order (MRO) to determine the order in which parent class methods are called. The MRO is a predictable order in which python searches for inherited methods.

Consider the following example:

class First:
    def __init__(self):
        print("First init")
        super().__init__()

class Second:
    def __init__(self):
        print("Second init")

class Third(First, Second):
    def __init__(self):
        print("Third init")
        super().__init__()

When you create an instance of Third and call its __init__() method, the output will be:

Third init
First init
Second init

This is because the MRO for Third is [Third, First, Second, object]. The super() call in Third calls First‘s __init__(), and the super() call in First calls Second‘s __init__() [[1]].