One issue here -- the instructions specify "None available!" but you have to output "None available" (no exclamation point) to pass

It doesn't have any bearing on the problem, but note that "3" is (in English-language terminology) an Arabic numeral, not a Roman numeral -- the Roman numeral for that value would be "III"

I'm having the same issue (with the Python version) -- I import the string module and then redefine cc, assigning it the return value of a call to string.replace(). It passes all the tests, but then doesn't work in this case when I attempt to submit it.