What is the Method Resolution Order (MRO)?

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The **MRO** is the deterministic, linear order in which Python searches a class and its bases for an attribute/method. With multiple inheritance, 'which `foo` wins?' is answered by walking the MRO left-to-right and using the first match. You can inspect it via `Cls.__mro__` or `Cls.mro()`.

Python computes it with the **C3 linearization** algorithm, which guarantees: a class appears **before** its parents, left-to-right order among bases is preserved, and each class appears **once**. If a consistent order can't be built (contradictory base orderings), the class definition raises `TypeError`.

**`super()`** doesn't simply mean 'the parent' — it means 'the **next class in the MRO**' relative to the current one. That's what makes **cooperative multiple inheritance** work: in a diamond (`D(B, C)`, `B`/`C` both extend `A`), each class's `super().method()` calls the next in line, so `A` runs **exactly once** instead of twice.

**Interview tip:** define MRO as C3 linearization and stress that

What is the Method Resolution Order (MRO)?

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