Assert Search.

=== assert (for tests, not user input) ===

assert condition, "message"

If the condition is False, Python raises AssertionError and stops — “fail loud” in tests. It does not replace if for input() validation.

def find_index(items, target):
    for i, value in enumerate(items):
        if value == target:
            return i
    return -1

assert find_index([3, 1, 4], 4) == 2 assert find_index([3, 1, 4], 9) == -1 print(find_index(["a", "b"], "b"))

Use assert after the function to check expected behavior. Task: write find_index, asserts, then print one real result.