Help me in solving DEBUGPYU14 problem

help
,
1

My issue

compiler throw error message when i summit

My code

for _ in range(int(input())): 

    N = int(input()) 

    s = list(input()) 

    for i in range(0, len(s)-1, 2): 

        s[i],s[i+1] = s[i+1],s[i] 

    for i in range(len(s)): 

        s[i] = chr(122 - ord(s[i]) + 97) 

    print(*s, sep='')

Learning course: Python with Data structures
Problem Link: Practice Problem in - CodeChef

2

First of all you have missed to declare a proper variable(ex: for i in range) in the first line
and second it maybe cause you have missed to assign a value to the last line
i.e. print(*s, sep=‘Your value should be assigned here.’)