In Python...

What this Python fundamentals interview question tests

This is a foundational Python knowledge question that appears in early-stage technical screening. It asks you to articulate a core design principle of the language—one that underpins how Python handles functions, classes, modules, and even primitive values.

Interviewers use questions like this to confirm that a candidate has moved beyond surface-level syntax to understand Python's object model. The answer reveals whether you grasp why certain language features work the way they do, and it often leads naturally into follow-up questions about identity, type, and method resolution.

• Python's object model and reference semantics
• Type checking and introspection
• How inheritance and polymorphism rely on this principle