You can find the skeleton code [[here|/code/untyped_evaluator.ml]].
The first place you need to add code is in the `free_in` function. You already
-wrote such a function [[in a previous homework|assignment5#occurs_free]], so this
+wrote such a function [[in a previous homework|exercises/assignment5-6#occurs_free]], so this
part should be easy. The intended behavior is for the function to return results
like this: