I'm quite happy with having found a way for this answer to not need the import.

My previous attempt was this: Try it online!

Is there a way to get rid of the let?

The only place let can't be shortened is when you're working with unique types.

in addition, if you require that the function be predefined under a symbolic name you can shorten that one more

tio.run/##DcxNC4IwGADgu7/…

@Laikoni ^ and you can use indexList tio.run/…

@Οurous Good to know. Have you considered adding a tips question for Clean?

tio.run/… this one is a bit more elegant

@Laikoni Actually I haven't. I should.

Is there a guide for writing them?

@Οurous None that I know of.

Usually they are just copied from another tips question.

That's why nearly all of them contain "What cgeneral tips do you have for golfing in uBasi? Any ideas that can be applied to code golf problems in general that are at least somewhat specific to uBasic. Please post one tip per answer."

And I assume one can answer their own tips question freely?

Yes, it is not a competition. You can directly post an answer when writing the question.

At least I did so here: codegolf.stackexchange.com/questions/150559/…

Question is up. I think that recent answer with StdEnv avoidance may be a good initial tip. "Avoiding imports"