Class methods and cls usage in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a class method using the correct decorator.

Python

class MyClass:
    [1]
    def greet(cls):
        return "Hello from class!"

Drag options to blanks, or click blank then click option'

A@classmethod

B@abstractmethod

C@property

D@staticmethod

Attempts:

3 left

💡 Hint

Common Mistakes

Using @staticmethod instead of @classmethod

Forgetting the decorator entirely

Using @property which is for attributes

The @classmethod decorator is used to define a method that receives the class itself as the first argument.

2fill in blank

medium

Complete the class method to return the class name using the cls parameter.

Python

class Animal:
    @classmethod
    def get_class_name([1]):
        return [1].__name__

Drag options to blanks, or click blank then click option'

Acls

Bclass

Cself

Dthis

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'self' which is for instance methods

Using reserved words like 'class'

Using 'this' which is not Python syntax

Class methods receive the class as the first parameter, usually named 'cls'.

3fill in blank

hard

Fix the error in the class method to correctly create an instance using cls.

Python

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

    @classmethod
    def create(cls, name):
        return [1](name)

Drag options to blanks, or click blank then click option'

Aname

Bself

CPerson

Dcls

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Person' directly which breaks inheritance

Using 'self' which is not defined in class methods

Using 'name' which is a string, not a class

Inside a class method, use 'cls' to create new instances so it works correctly with subclasses.

4fill in blank

hard

Fill both blanks to define a class method that counts how many instances were created.

Python

class Counter:
    count = 0

    def __init__(self):
        Counter.count += 1

    @[1]
    def get_count([2]):
        return [2].count

Drag options to blanks, or click blank then click option'

Aclassmethod

Bcls

Cstaticmethod

Dself

Attempts:

3 left

💡 Hint

Common Mistakes

Using @staticmethod which does not receive class or instance

Using 'self' in a class method

Forgetting the decorator

The method must be decorated with @classmethod and receive 'cls' to access class variables.

5fill in blank

hard

Fill all three blanks to create a class method that returns a dictionary with uppercase class name as key and count as value.

Python

class Tracker:
    count = 0

    def __init__(self):
        Tracker.count += 1

    @[1]
    def summary([2]):
        return { [3]: [2].count }

Drag options to blanks, or click blank then click option'

Aclassmethod

Bcls

Ccls.__name__.upper()

Dself

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'self' instead of 'cls' in class method

Using @staticmethod instead of @classmethod

Using a string literal instead of cls.__name__.upper()

Use @classmethod and 'cls' parameter; the key is the uppercase class name accessed by cls.__name__.upper().