thanks alot
I'll fix it

That's exactly your problem, you should be using them.

Not a kata issue, check what the delimiters value is.

['some', 'strange', 'string'] should equal ['some strange string']
['1', '2', '3'] should equal ['1+2', '-', '3']

I think there is something wrong with those tests
in python

thank you
finally I got it

Have you read the error message?

X will be either a number or a string. Both are valid.

You need to do something for that to work with strings.