Multiple inheritance syntax in Python - Step-by-Step Execution

Concept Flow - Multiple inheritance syntax

Define Parent1 class

↓

Define Parent2 class

↓

Define Child class(Parent1, Parent2)

↓

Create Child object

↓

Access methods/attributes from Parent1 and Parent2

↓

Use Child object

Multiple inheritance means a class can inherit from more than one parent class, gaining their methods and properties.

Execution Sample

Python

class Parent1:
    def greet(self):
        return "Hello from Parent1"

class Parent2:
    def greet(self):
        return "Hello from Parent2"

class Child(Parent1, Parent2):
    pass

c = Child()
print(c.greet())

This code shows a Child class inheriting from two parents and calling the greet method.

Execution Table

Step	Action	Evaluation	Result
1	Define class Parent1 with greet method	No output	Parent1 class created
2	Define class Parent2 with greet method	No output	Parent2 class created
3	Define class Child inheriting Parent1 and Parent2	No output	Child class created with multiple inheritance
4	Create object c of class Child	No output	Object c created
5	Call c.greet()	Look for greet in Child, then Parent1, then Parent2	"Hello from Parent1"
6	Print output of c.greet()	Output to console	Hello from Parent1

💡 Execution stops after printing the greeting from Parent1 due to method resolution order.

Variable Tracker

Variable	Start	After Creation	Final
c	undefined	Child object created	Child object with access to Parent1 and Parent2 methods

Key Moments - 2 Insights

Why does c.greet() call Parent1's greet and not Parent2's?

Because Python uses method resolution order (MRO) which checks Parent1 first as it is listed first in Child(Parent1, Parent2). See execution_table step 5.

Can Child override greet method?

Yes, Child can define its own greet method which will be called instead of parents'. This is not shown here but is possible.

Visual Quiz - 3 Questions

Look at the execution table, what is printed at step 6?

A Error: ambiguous method

B "Hello from Parent2"

C "Hello from Parent1"

D "Hello from Child"

💡 Hint

Check step 5 and 6 in execution_table where c.greet() returns Parent1's greeting.

At which step is the Child object created?

A Step 4

B Step 3

C Step 5

D Step 2

💡 Hint

Look at execution_table step 4 where object c is created.

If Parent1 was listed after Parent2 in Child's definition, which greet would be called?

A Parent1's greet

B Parent2's greet

C Child's greet

D Error due to conflict

💡 Hint

Method resolution order checks parents in the order they are listed in class definition.

Concept Snapshot

Multiple inheritance syntax in Python:
class Child(Parent1, Parent2):
    pass

Child inherits methods from both parents.
Method resolution order (MRO) decides which parent's method is used.
Order matters: first parent checked first.
Child can override any inherited method.

Full Transcript

This visual execution shows how Python handles multiple inheritance syntax. First, two parent classes Parent1 and Parent2 are defined, each with a greet method. Then, a Child class inherits from both parents using class Child(Parent1, Parent2). When we create an object c of Child and call c.greet(), Python looks for greet in Child first, then Parent1, then Parent2. Since Child has no greet, it uses Parent1's greet because Parent1 is listed first. The output is 'Hello from Parent1'. This example helps understand how multiple inheritance works and how Python decides which method to use when parents have methods with the same name.