Python Multiple Inheritance

1. What is Multiple Inheritance

Multiple inheritance occurs when a class inherits from more than one parent class.

class Father:
    def skill1(self):
        print("Driving")

class Mother:
    def skill2(self):
        print("Cooking")

class Child(Father, Mother):
    pass

c = Child()
c.skill1()
c.skill2()

The child class gains features from all parent classes.

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2. Basic Multiple Inheritance Structure

class A:
    def show_a(self):
        print("Class A")

class B:
    def show_b(self):
        print("Class B")

class C(A, B):
    pass

obj = C()
obj.show_a()
obj.show_b()

The child class can access methods from both parents.

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3. Overlapping Method Names

class A:
    def display(self):
        print("From A")

class B:
    def display(self):
        print("From B")

class C(A, B):
    pass

obj = C()
obj.display()

Python follows Method Resolution Order (MRO) to determine which method to invoke.

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4. Understanding Method Resolution Order (MRO)

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

class B:
    def show(self):
        print("B")

class C(A, B):
    pass

print(C.mro())

MRO defines the order of class traversal: C → A → B → object

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5. Calling Parent Methods Explicitly

class A:
    def process(self):
        print("Process A")

class B:
    def process(self):
        print("Process B")

class C(A, B):
    def process(self):
        A.process(self)
        B.process(self)

c = C()
c.process()

Allows execution of logic from multiple parents.

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6. Multiple Inheritance with Constructors

class A:
    def __init__(self):
        print("Constructor A")

class B:
    def __init__(self):
        print("Constructor B")

class C(A, B):
    def __init__(self):
        super().__init__()

c = C()

Only the first parent’s constructor executes due to MRO.

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7. Cooperative Multiple Inheritance Using super()

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

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

class C(A, B):
    def __init__(self):
        print("C init")
        super().__init__()

c = C()

Demonstrates cooperative method chaining through MRO.

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8. Diamond Problem Example

class Grandparent:
    def greet(self):
        print("Hello from Grandparent")

class Parent1(Grandparent):
    pass

class Parent2(Grandparent):
    pass

class Child(Parent1, Parent2):
    pass

c = Child()
c.greet()

Python resolves this ambiguity using MRO, avoiding duplicate calls.

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9. Visualizing the Inheritance Hierarchy

class X:
    pass

class Y(X):
    pass

class Z(X):
    pass

class W(Y, Z):
    pass

print(W.mro())

Helps understand order of class resolution for debugging.

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10. Real-World Multiple Inheritance Example

class Logger:
    def log(self):
        print("Logging data")

class Validator:
    def validate(self):
        print("Validating data")

class Service(Logger, Validator):
    def execute(self):
        self.log()
        self.validate()
        print("Executing service")

service = Service()
service.execute()

Combines cross-cutting concerns such as logging and validation.

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