TutorSyntax A-level Python | Lesson 3: Stacks and LIFO

Learning goal: Implement push, pop and peek using a list, including underflow handling.

1. Read the worked example on the site.
2. Complete the starter without looking at the solution.
3. Add normal, boundary and invalid tests.
4. Compare with the reference solution; explain your improvements.

A-level note: OCR H446 data structures / AQA 7517 data structures. These are original practice materials, not endorsed exam-board tasks.
