No problem, you're welcome.

Not a kata issue, read this (specially How do I post to a kata discourse? and How can I see which input causes my solution to fail?) and the error message in detail, it's saying why your code fails:

Traceback (most recent call last):
  File "/runner/frameworks/python/cw-2.py", line 111, in wrapper
    func()
  File "main.py", line 5, in basic
    test.assert_equals(format_duration(0), "now")
  File "/home/codewarrior/solution.py", line 50, in format_duration
    }[min(5, n)].format(*result[:5])
KeyError: 0

Also, this part of the instructions:

The function must accept a non-negative integer. If it is zero, it just returns "now".