Yes, I was wrong.

Hi g964, thank you for this interesting challenge.
I'm done this task in Xcode in Swift because I learning it now. But want pay attention to your testing examples.
In your example of "coding" result in your coded string there are 2 spaces after "\nk" before "mg" so the assert string will be

"c nhsoI\nltiahi \noentinw\ncng nga\nk{TWO SPACES HERE}mg s\n\voao f \n\v'trtig"

to pass the code() function tests well.

The same issue in Test 5

Test5
✘ Expected: True
But was: False
at AreTheySameTests.Test5 () <0x40826f20 + 0x0009f> in :0

a [ 121 144 19 161 19 144 19 11 1008 ]
b [ 121 14641 20736 36100 25921 361 20736 361 ]
Not found 190

190 * 190 = 36100 that is exists in b
but there are no 190 in a