Help me in solving DNASTORAGE problem

My issue

how?

My code

# cook your dish here
t=int(input())
for __ in range(t):
  i=0
  
  if()

Learning course: Strings using Python
Problem Link: CodeChef: Practical coding for everyone

@vishnupriya186
here is the correct python code.
plzz refer it for better understanding .

# cook your dish here
a=int(input())
for i in range(a):
    n=int(input())
    b=input()
    for j in range(0,n,2):
        
        if(b[j]=="0"):
            if(b[j+1]=="0"):
                print("A",end="")
            elif(b[j+1]=="1"):
                print("T",end="")
        elif(b[j]=="1"):
            if(b[j+1]=="0"):
                print("C",end="")
            elif(b[j+1]=="1"):
                print("G",end="")
    print()