this is a really nice solution. I code-golfed my way to a one-liner but I love your use of compose() here. Very elegant.

This took me a really long time (almost the whole day) and I struggled a lot. I found the previous exercises in the series fairly simple but this one I really struggled with.
I plodded on, searching online for various things and I seemed to be progressing. I started by commenting out all but the first / simplest test, and worked to get that working. Once it did, I uncommented the next... now I have to deal with the iteration on creation... then I revealed the next one etc... that definitely made it more manageable... but then when submitting, I hit the createFilter tests... I swear, it simply wasn't clear to me how that was supposed to work at all. At this point I was guessing and it seemed like no combination of logic would get my tests to pass.
Eventually I did 'reveal solutions' which meant that I didn't get credit for completion, but I actually learned that I was super close and it was simpler than I thought.
I would have like to have seen the createFilter tests in the main Kata versus hidden until submission.

I got through, and I think I learned something about streams and conversions etc., but I have to be honest I don't think I'll retain what I took from creating the custom functions or predicate... They still seem obtuse to me and when I look at the code that was created as a result, it doesn't necessarily make sense to me why I'd use these.

Really enjoyed the series, thank you! This one was tough for me.

It's like that in Sample tests and kata description too, and it's been like that for a long time. Changing it now would render all solutions invalid.

Why do the full tests when submitting the Java version call a method called Line.Tickets() instead of Line.tickets() (upper case T instead of lower)??!?