Answer.

History of the question:

The super() function was introduced to simplify working with inheritance. Before its introduction, it was necessary to explicitly specify the name of the parent class when calling methods of the ancestor, which made mixins and multiple inheritance inconvenient and could lead to errors. super() takes the inheritance order (MRO) into account.

Problem:

In multiple inheritance, directly referencing the parent class often only calls its methods, ignoring other ancestors. This breaks the chain of calls. The task of super() is to correctly construct the method chain considering the hierarchy.

Solution:

super() returns a proxy object that delegates calls to the next class in the MRO line. This allows for a uniform way to call methods of all ancestors down the chain.

Code example:

class A:
    def show(self):
        print("A.show()")

class B(A):
    def show(self):
        print("B.show() -> ", end="")
        super().show()

class C(A):
    def show(self):
        print("C.show() -> ", end="")
        super().show()

class D(B, C):
    def show(self):
        print("D.show() -> ", end="")
        super().show()

d = D()
d.show()
# Output: D.show() -> B.show() -> C.show() -> A.show()

Key features:

• super() follows MRO (Method Resolution Order) and does not depend on class names.
• Works only with new-style classes (in Python 3, all classes are new-style).
• Used for correct initialization and handling of multiple inheritance.

Tricky questions.

Can you use super without arguments in static methods?

No, in static methods there are neither self nor cls. super() expects to be called from an instance or class method, where there is information about the object's type.

Will the parent method be called if it was skipped in the super() call chain?

No. If you do not call super() in the chain, the execution will not "pass" further. Therefore, when overriding methods, it's important to always remember about super(), otherwise part of the ancestor's logic will be skipped.

Can you pass arbitrary arguments to super()?

Yes, but the usual form of super() without arguments (in Python 3) helps avoid errors and looks cleaner. Passing arguments is necessary only in rare cases (e.g., compatibility with Python 2) and is usually not needed.

Common mistakes and anti-patterns

Pros:

• Allows avoiding code duplication in hierarchies.
• Ensures call consistency for all ancestors. Cons:
• Errors in MRO lead to hard-to-detect bugs.
• Skipping super() breaks the entire call chain.

Real-life example

Negative case: In a large project, the parent class contained initialization, but one of the child classes forgot to call super().init(). As a result, partially initialized objects appeared with uninitialized attributes.

Pros: did not require manually calling each parent class. Cons: difficulty in tracking if someone missed super().

Positive case: A well-implemented super() chain ensured correct initialization of all base classes, simplifying maintenance and development of the architecture.

Pros: code cleanliness, ease of extension. Cons: easy to make mistakes in complex MRO — understanding the order of calls is required.