Hello, Agent Double-Null0111.
Your mission, should you choose to accept it, is to write a pair of tools to help you infiltrate UMBRA (United Minions Being Really Awful) headquarters and retrieve the plans for their latest really awful scheme. There are two tools you will need to carry out this mission.
The story facilitates defining higher-order functions including a function that takes a function as input and a function that returns a function as output: