Challenge 2: Validated Age Input — Possible Solution
====================================================================

def set_age(age):
    if age < 0:
        raise ValueError("Age cannot be negative")
    return age

try:
    print(set_age(25))
except ValueError as e:
    print(f"Error: {e}")

try:
    print(set_age(-5))
except ValueError as e:
    print(f"Error: {e}")

Output:
25
Error: Age cannot be negative

WHY THIS WORKS AS AN ANSWER
------------------------------
set_age(age) reuses the exact raise ValueError("message") pattern
from the chapter's own withdraw() example — if age < 0, it raises a
ValueError carrying the specific message "Age cannot be negative"
rather than letting some unrelated, less clear error occur later.

The first call, set_age(25), never triggers the if age < 0 branch at
all, so the function just returns 25 normally, and the try block's
print(set_age(25)) runs to completion — the except block is skipped
entirely, the same "except only runs if an exception actually occurs"
behavior covered throughout the chapter.

The second call, set_age(-5), does trigger the raise, so control
jumps out of the try block immediately (never reaching a return) and
into except ValueError as e:. The as e clause captures the exception
object, and the chapter's own f"Error: {e}" pattern extracts its
message directly, printing "Error: Age cannot be negative".