He means that you should print the parameters and check their value and then figure out why your code doesn't work on that specific input. console.log is how you do it in javascript, in python you'd probably use print instead.

what dose this mean?
I use python, 65passed and the only fail is 'codewars is not 2xcode'
Do you mean 'Params' equals to ':'?

I got same problem on same test case, after print out x and y.
x = 'abc', y = 'ac', instead of accept 'a' or 'c',

Result:
Expected: ac, instead got: c

is this correct?

console.log('Params:', s, ':', part1, ':', part2);

[javascript]
only this one fail, what does this mean exactly?

✘ codewars is not 2xcode