Workspace demo: JupyterLab (Python)

This is a workspace question with an in-browser JupyterLab.

The Fibonacci numbers are 1, 1, 2, 3, 5, 8, ..., where each number is the sum of the two before it. These are numbered $F_1, F_2, \ldots$, and \[ F_n = F_{n-1} + F_{n-2}. \]

In the notebook Workbook.ipynb, you will be prompted to write a Python function fib that takes a number n and returns the n^th Fibonacci number, $F_n$.