I think referring to Codewars Test Docs will help.

Exception is the vague part because the test output just says Test Failed Exception:Exception Exception:Exception

I was able to get it to pass with a specific Excpetion such as InputException. Also seing the solutions now, there are a few different options here but it can't just be raising an Exception. Hopefully this is more clear.

Description is very vague, but basically author is expecting You to raise an exception if:
a) any char in the string is not a number
b) passed string is empty