def rfind(
        self,
        sub: str | bytes | Any,
        start: int | Any = 0,
        end: int | Any = None,
    ) -> T_DataArray:
        """
        Return highest indexes in each strings in the array
        where the substring is fully contained between [start:end].
        Return -1 on failure.

        If `start`, `end`, or 'sub` is array-like, they are broadcast
        against the array and applied elementwise.

        Parameters
        ----------
        sub : str or array-like of str
            Substring being searched.
            If array-like, it is broadcast.
        start : int or array-like of int
            Left edge index.
            If array-like, it is broadcast.
        end : int or array-like of int
            Right edge index.
            If array-like, it is broadcast.

        Returns
        -------
        found : array of int
        """
        return self.find(sub, start=start, end=end, side="right")

        Return highest indexes in each strings in the array
        where the substring is fully contained between [start:end].
        Return -1 on failure.

        If `start`, `end`, or 'sub` is array-like, they are broadcast
        against the array and applied elementwise.

        Parameters
        ----------
        sub : str or array-like of str
            Substring being searched.
            If array-like, it is broadcast.
        start : int or array-like of int
            Left edge index.
            If array-like, it is broadcast.
        end : int or array-like of int
            Right edge index.
            If array-like, it is broadcast.

        Returns
        -------
        found : array of int
        
xarray/core/accessor_str.py