agree

The one place you write code

Graded on agreement with a reference the engine owns, on inputs it chose — never on style, and never on a suite you can read. A function that returns the right answer and changes what it was handed has not agreed, which is the only correct grading here. You still have to say what the program does first.

• hardWrite `withTag`, which returns a list with the tag added. First say what the reference does to its argument.