It is a 7 kyu so what's your point?

Nevermind, the problem you experience is because you're mutating the original list.

l = [1,2,3]
n = l
n is l # returns True
del n[0]
l == [2, 3] # returns True

Make a copy of l to fix your problem.

If so, please do the following:

• Make absolutely sure the problem is not in your code
• Add a comment labeled as "Issue"
• Describe in detail what you experience and what you expect, and in what language

If there is an issue, someone might come and fix it. However, it's just not possible to fix "a problem" in unknown language.