__name__ == '__main__' guard

Question

Accepted Answer

When Python runs a file directly, it sets `__name__` to `'__main__'`. When the same file is imported as a module, `__name__` becomes the module's name instead. The guard lets you write code - like `main()` calls or test scaffolding - that only fires during direct execution. Without it, that code would run every time someone imported the file, which can cause unexpected side effects in tests or other scripts.