Prerequisites — what you should know before this track — Senior Deep-Dives

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Task

📝 **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.

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The GIL — what it is, what it isn't

🔮 Predict the output

Read the code carefully

def add_item(item, bucket=[]):
    bucket.append(item)
    return bucket

a = add_item("x")
b = add_item("y")
print(a)
print(b)
print(a is b)

What will the program print? Write here:

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