Multiple inheritance syntax in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a class Child that inherits from Parent1 and Parent2.

Python

class Child([1]):
    pass

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

A[Parent1, Parent2]

BParent1 Parent2

CParent1, Parent2

D(Parent1, Parent2)

Attempts:

3 left

💡 Hint

Common Mistakes

Using spaces instead of commas between parent classes.

Using square brackets instead of parentheses.

Omitting parentheses entirely.

In Python, multiple inheritance is declared by listing parent classes separated by commas inside the parentheses after the class name.

2fill in blank

medium

Complete the code to create an instance of Child class.

Python

obj = [1]()

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

Aparent2

Bchild

CParent1

DChild

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase letters for class names.

Trying to instantiate parent classes instead of the child.

Class names are case-sensitive in Python. The class defined is Child, so the instance must be created with Child().

3fill in blank

hard

Fix the error in the class definition to correctly inherit from ParentA and ParentB.

Python

class MyClass([1]):
    pass

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

AParentA, ParentB

BParentA ParentB

C[ParentA, ParentB]

DParentA.ParentB

Attempts:

3 left

💡 Hint

Common Mistakes

Using spaces instead of commas.

Using square brackets or dot notation.

Multiple inheritance requires listing parent classes separated by commas inside parentheses.

4fill in blank

hard

Fill both blanks to define a class MultiChild that inherits from Base1 and Base2 and create an instance named instance.

Python

class MultiChild([1]):
    pass

instance = [2]()

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

ABase1, Base2

BMultiChild

CBase1

DBase2

Attempts:

3 left

💡 Hint

Common Mistakes

Using only one parent class in inheritance.

Trying to instantiate a parent class instead of the child.

The class inherits from both Base1 and Base2 separated by commas. The instance is created from the class MultiChild.

5fill in blank

hard

Fill all three blanks to define a class FinalChild inheriting from Alpha and Beta, create an instance obj, and call its method().

Python

class FinalChild([1]):
    def method(self):
        return "Hello"

obj = [2]()
print(obj.[3]())

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

AAlpha, Beta

BFinalChild

Cmethod

DBeta

Attempts:

3 left

💡 Hint

Common Mistakes

Using only one parent class.

Calling a method that does not exist.

Using wrong class or method names.

The class inherits from Alpha and Beta. The instance is created from FinalChild. The method called is 'method'.

Practice

1. What is the correct way to declare a class Child that inherits from two parent classes Parent1 and Parent2 in Python?

easy

A. class Child(Parent1, Parent2):

B. class Child(Parent1 & Parent2):

C. class Child inherits Parent1, Parent2:

D. class Child: Parent1, Parent2

Solution

1. Step 1: Understand Python class inheritance syntax

   In Python, to inherit from multiple classes, list them separated by commas inside parentheses after the class name.

2. Step 2: Match the syntax to the options

   class Child(Parent1, Parent2): uses the correct syntax: class Child(Parent1, Parent2):. Other options use invalid syntax.

3. Final Answer:

   class Child(Parent1, Parent2): -> Option A

4. Quick Check:

   Multiple inheritance syntax = class Child(Parent1, Parent2): [OK]

Hint: List parent classes separated by commas in parentheses [OK]

Common Mistakes:

• Using '&' instead of commas between parent classes
• Writing 'inherits' keyword like other languages
• Not using parentheses after class name

2. Which of the following is a syntax error when defining a class with multiple inheritance?

easy

A. class MyClass(): pass

B. class MyClass(Parent1, Parent2): pass

C. class MyClass(Parent1): pass

D. class MyClass(Parent1 Parent2): pass

Solution

1. Step 1: Check syntax for multiple inheritance

   Parent classes must be separated by commas inside parentheses.

2. Step 2: Identify the incorrect option

   class MyClass(Parent1 Parent2): pass misses the comma between Parent1 and Parent2, causing a syntax error.

3. Final Answer:

   class MyClass(Parent1 Parent2): pass -> Option D

4. Quick Check:

   Missing comma between parents = SyntaxError [OK]

Hint: Always separate parent classes with commas [OK]

Common Mistakes:

• Omitting commas between parent classes
• Leaving out parentheses entirely
• Using colons instead of commas

3. What will be the output of this code?

class A:
    def greet(self):
        return "Hello from A"

class B:
    def greet(self):
        return "Hello from B"

class C(A, B):
    pass

obj = C()
print(obj.greet())

medium

A. "Hello from A"

B. TypeError

C. AttributeError

D. "Hello from B"

Solution

1. Step 1: Understand method resolution order (MRO)

   Class C inherits from A first, then B. Python looks for methods in the order of parents listed.

2. Step 2: Determine which greet() is called

   Since A is first, C uses A's greet method, returning "Hello from A".

3. Final Answer:

   "Hello from A" -> Option A

4. Quick Check:

   MRO follows parent order = "Hello from A" [OK]

Hint: First parent class method is used in multiple inheritance [OK]

Common Mistakes:

• Assuming last parent class method is called
• Expecting an error due to multiple parents
• Confusing method names or forgetting MRO

4. Find the error in this multiple inheritance code:

class X:
    pass

class Y:
    pass

class Z(X Y):
    pass

medium

A. Missing colon after class name

B. Missing comma between parent classes

C. Parent classes must be in square brackets

D. Class Z cannot inherit from X and Y

Solution

1. Step 1: Check syntax for multiple inheritance

   Parent classes must be separated by commas inside parentheses.

2. Step 2: Identify the syntax error

   In class Z(X Y):, the comma between X and Y is missing, causing a syntax error.

3. Final Answer:

   Missing comma between parent classes -> Option B

4. Quick Check:

   Comma missing between parents = SyntaxError [OK]

Hint: Separate parent classes with commas inside parentheses [OK]

Common Mistakes:

• Forgetting commas between parent classes
• Using square brackets instead of parentheses
• Thinking multiple inheritance is not allowed

5. Given these classes:

class Alpha:
    def action(self):
        return "Alpha"

class Beta:
    def action(self):
        return "Beta"

class Gamma(Alpha, Beta):
    def action(self):
        return super().action() + " & Gamma"

class Delta(Gamma, Beta):
    pass

obj = Delta()
print(obj.action())

What is the output?

hard

A. "Beta & Gamma"

B. "Gamma"

C. "Alpha & Gamma"

D. AttributeError

Solution

1. Step 1: Understand the inheritance chain and MRO

   Delta inherits from Gamma and Beta. Gamma inherits from Alpha and Beta. The MRO for Delta is Delta, Gamma, Alpha, Beta, object.

2. Step 2: Trace the action() method call

   Delta uses Gamma's action(), which calls super().action(). In Gamma, super() refers to Alpha (next in MRO), so Alpha.action() returns "Alpha". Then Gamma appends " & Gamma".

3. Final Answer:

   "Alpha & Gamma" -> Option C

4. Quick Check:

   super() follows MRO = "Alpha & Gamma" [OK]

Hint: super() calls next in MRO, not just first parent [OK]

Common Mistakes:

• Assuming super() calls Beta's method instead of Alpha's
• Ignoring MRO order in multiple inheritance
• Expecting an error due to complex inheritance