This is a version of the exercise that makes the tables correctly:

This is a version that includes a conditional (a conditional that definitely, definitely doesn’t work):

I don’t know that we had the knowledge necessary to complete this. James and I spent the weekend on this. I spent nearly 12 hours on it over the course of the weekend, and I don’t think it was supposed to take this long. It was incredibly frustrating. I am proud of the fact that I managed to make the dictionary of dictionaries and that we got the joining to function. Why the conditional does not function, we are not sure. It seems that it ought to, given that everything functions correctly without it, but we don’t know what’s happening there. We’re looking forward to seeing the solution to this, and hope it clarifies the difficulties we had.