puzzle = [[1, 2, 3, 4, 5],
            [6, 7, 8, 9, 10],
            [11,12,13,14,15],
            [16,17,18,19,20],
            [21,22,23,24,25]]

puzzle = [[1, 2, 3, 4, 5],
            [6, 2, 8, 9, 10],
            [11,12,13,14,15],
            [16,17,18,19,20],
            [21,22,23,24,25]]

def check_columns_valid(puzzle):

  for i in range(len(puzzle)):
     if i[0] == i[5]  == i[10] ==  i[15] == i[20]:
        return False
     elif i[1] == i[6] == i[11] == i[16] == i[21]:
        return False
     elif i[2] == i[7] == i[12] == i[17] == i[22]:
        return False
     elif i[3] == i[8] == i[13] == i[18] == i[23]:
        return False
     elif i[4] == i[9] == i[14] == i[19] == i[24]:
        return False
   return True