Why use ''.join() in chapter 14, solution 1, find_orfs()?

[Chase W. Nelson｜倪誠志]

For the following line in chapter 14, solution 1, find_orfs(), from page 281:

orfs.append(''.join(aa[start:stop]))

Could you help me understand why one would not use the following (presumably simpler?):

orfs.append(aa[start:stop])

In other words, what is the advantage of joining on the empty string in this situation?

Thanks as always!
Chase

[Ken Youens-Clark]

Chase,

Actually, there are no advantages, and leaving out the join correct. I must have been thinking about ensuring this was a str and not a list. Thanks for the catch.

Ken