# Bad index in a sublist

In the following code

```
A=[[99999,99999,1,99999],[1,99999,1,99999]]
A[0].index(A[0][2])
A[0].index(A[0][0])
A[0].index(A[0][1])
```

The index returned is the true one if the value is encountered form the first time in the 0th element of `A`

. So `A[0].index(A[0][2])`

and `A[0].index(A[0][0])`

give the good index. But not `A[0].index(A[0][1])`

. Why ?