else, finally, and Raising

Scenario: A lock must release whether deployment succeeds or fails.

New words, in plain English

• else clause - runs when try completed without exception
• finally clause - runs whether an exception happened or not
• raise - create or re-throw an exception

Use else for success-only work and finally for unavoidable cleanup. raise rejects invalid state; bare raise re-throws the current exception.

Analogy: A Python program is like a clear set of instructions for a careful helper: names label things, indentation groups steps, and errors explain where the helper became confused.

A small, real example

handle = open("deploy.log", "a")
try:
    handle.write("start\n")
else:
    print("logged")
finally:
    handle.close()

Tip: A with statement is usually cleaner than manual open/finally for files.

Goal: Practice this idea in the py-exception-handling challenge at /labs/python. Fix the broken program, run it yourself, then use check to prove the real end state.