Modules & Imports

Why this matters

Circular imports and misuse of __name__ == "__main__" are the top reasons Django and Flask apps fail to boot. Understanding sys.path, package __init__.py, and relative imports is what makes monorepos and installable packages actually work.

Common pitfalls

• Circular imports from top-level from x import y — defer imports into function bodies or restructure modules.
• Running python module.py inside a package — relative imports break; use python -m package.module.
• Shadowing stdlib names like email.py or types.py in your project — silently breaks unrelated imports.