Help me figure out why this python code doesn't work

Hi, yeah i know this isn't place for this, but i'm not sure where else i could post it so i might as well give it a shot.

i'm writing a python code that checks if sudoku is solved correctly, and i have problems at the very start. I have this so far

def testsudoku(sudoku):

for i in range(9):
     test=[0,0,0,0,0,0,0,0,0]
     for j in range(9):
         test[sudoku[i][j]]+=1

     for k in range(9):
         if test[k] >1:
             return 'Nije dobar sudoku, greska u ', i, '-tom redu, i ', k, '-toj koloni'

return 'sudoku je dobar'                 

sudoku=[[2,9,5,3,1,6,8,4,7], [3,4,8,7,9,2,6,1,5], [6,7,1,5,4,8,9,2,3], [5,6,3,2,8,9,1,7,4], [1,8,7,6,3,4,2,5,9], [4,2,9,1,5,7,3,6,8], [7,3,6,8,2,5,4,9,1], [8,5,4,9,6,1,7,3,2], [9,1,2,4,7,3,5,8,6]]

testsudoku(sudoku)

I get an error in line test[sudoku[i][j]]+=1 saying IndexError: list index out of range. If i write the same thing with numbers and not i and j it works fine and since range(9) returns numbers from 0 to 8 it should also be ok. I'm not quite sure what the problem is but i'd appreciate help.