I've misunderstood the point. How about this?
```
    index : a column, Grouper, or list of them. Or an array which has the same length as data.
        Keys to group by on the pivot table index.
        If an array is passed, it is being used as a mapping from data to new index labels.
    columns : a column, Grouper, or list of them. Or an array which has the same length as data.
        Keys to group by on the pivot table column.
        If an array is passed, it is being used as a mapping from data to new column labels.
```