📝 **Task:** Read the snippet below. Predict the **exact output** (one line). This exercises the senior-grade pattern this track opens with — Python's reference semantics on mutable defaults / shared lists. If you can predict this, you're ready for sr-01 (the GIL deep-dive). If you can't, FastAPI + Project Studio first. 📋 Implement the function above. Tests run automatically. 💡 **Hint:** Re-read the theory if you get stuck.