Multiple Inheritance

MRO Notes

MRO: Method Resolution Order. Determines the order in which methods are searched for during inheritance in Python. Python uses the C3 linearization algorithm for its MRO.

Crucial for understanding how inheritance works, especially with multiple inheritance. Incorrect MRO can lead to unexpected behavior.

C3 Linearization (This will be a separate note explaining the C3 algorithm)

Example:

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

class B(A):
    def method(self):
        print("B")

class C(A):
    def method(self):
        print("C")

class D(B, C):
    pass

d = D()
d.method() # Output: B (because of [MRO](./../mro/))

print(D.__mro__) # Shows the [MRO](./../mro/): (<class '__main__.D'>, <class '__main__.B'>, <class '__main__.C'>, <class '__main__.A'>, <class 'object'>)

Things to explore further:

• Diamond problem (and how Python’s MRO solves it) Diamond Problem
• Impact of MRO on super() super()
• MRO in different Python versions (though unlikely to change significantly)

Related Notes:

• Inheritance
• Multiple Inheritance