Exceptions and try/except

Scenario: One malformed port in a configuration should produce a useful message, not a mystery crash.

New words, in plain English

• Exception - an object describing an error during execution
• Traceback - the call path showing where an unhandled exception happened
• except block - code handling a matching exception type

Put only the risky operation in try. Catch specific types such as ValueError and FileNotFoundError; broad catches can hide programming bugs.

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

try:
    port = int("not-a-port")
except ValueError as error:
    print(f"Invalid port: {error}")

Tip: An exception message should add context without discarding the original cause.

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.