So ladies and gentlemen...

In one of the tests I get the following

Expected: equal to "1, 1, 2, 3, 5, 8, 13, 21, 34, 55"
actual: ""

How am I supposed to guess where the problem is? How should I understand which Brainf**k language command was used? How should I understand whether the string was supplemented with some characters or not (unless, of course, I need to know this at all)

Your options, dear)

I had to tinker, the task with strings is interesting, but there are nuances.
I tried to find a solution without using regular expressions, maybe that's why it turned out hard.
The condition is not quite complete, (underscores, double spaces for example). However, the task describes a completely working situation, when you need to take into account all the nuances, even if for some reason they are not displayed in the tests.