def isel(
        self,
        indexers: Mapping[Any, Any] | None = None,
        drop: bool = False,
        missing_dims: ErrorOptionsWithWarn = "raise",
        **indexers_kwargs: Any,
    ) -> Self:
        """Returns a new data tree with each array indexed along the specified
        dimension(s).

        This method selects values from each array using its `__getitem__`
        method, except this method does not require knowing the order of
        each array's dimensions.

        Parameters
        ----------
        indexers : dict, optional
            A dict with keys matching dimensions and values given
            by integers, slice objects or arrays.
            indexer can be a integer, slice, array-like or DataArray.
            If DataArrays are passed as indexers, xarray-style indexing will be
            carried out. See :ref:`indexing` for the details.
            One of indexers or indexers_kwargs must be provided.
        drop : bool, default: False
            If ``drop=True``, drop coordinates variables indexed by integers
            instead of making them scalar.
        missing_dims : {"raise", "warn", "ignore"}, default: "raise"
            What to do if dimensions that should be selected from are not present in the
            Dataset:
            - "raise": raise an exception
            - "warn": raise a warning, and ignore the missing dimensions
            - "ignore": ignore the missing dimensions

        **indexers_kwargs : {dim: indexer, ...}, optional
            The keyword arguments form of ``indexers``.
            One of indexers or indexers_kwargs must be provided.

        Returns
        -------
        obj : DataTree
            A new DataTree with the same contents as this data tree, except each
            array and dimension is indexed by the appropriate indexers.
            If indexer DataArrays have coordinates that do not conflict with
            this object, then these coordinates will be attached.
            In general, each array's data will be a view of the array's data
            in this dataset, unless vectorized indexing was triggered by using
            an array indexer, in which case the data will be a copy.

        See Also
        --------
        DataTree.sel
        Dataset.isel
        """

        def apply_indexers(dataset, node_indexers):
            return dataset.isel(node_indexers, drop=drop)

        indexers = either_dict_or_kwargs(indexers, indexers_kwargs, "isel")
        return self._selective_indexing(
            apply_indexers, indexers, missing_dims=missing_dims
        )
Returns a new data tree with each array indexed along the specified
        dimension(s).

        This method selects values from each array using its `__getitem__`
        method, except this method does not require knowing the order of
        each array's dimensions.

        Parameters
        ----------
        indexers : dict, optional
            A dict with keys matching dimensions and values given
            by integers, slice objects or arrays.
            indexer can be a integer, slice, array-like or DataArray.
            If DataArrays are passed as indexers, xarray-style indexing will be
            carried out. See :ref:`indexing` for the details.
            One of indexers or indexers_kwargs must be provided.
        drop : bool, default: False
            If ``drop=True``, drop coordinates variables indexed by integers
            instead of making them scalar.
        missing_dims : {"raise", "warn", "ignore"}, default: "raise"
            What to do if dimensions that should be selected from are not present in the
            Dataset:
            - "raise": raise an exception
            - "warn": raise a warning, and ignore the missing dimensions
            - "ignore": ignore the missing dimensions

        **indexers_kwargs : {dim: indexer, ...}, optional
            The keyword arguments form of ``indexers``.
            One of indexers or indexers_kwargs must be provided.

        Returns
        -------
        obj : DataTree
            A new DataTree with the same contents as this data tree, except each
            array and dimension is indexed by the appropriate indexers.
            If indexer DataArrays have coordinates that do not conflict with
            this object, then these coordinates will be attached.
            In general, each array's data will be a view of the array's data
            in this dataset, unless vectorized indexing was triggered by using
            an array indexer, in which case the data will be a copy.

        See Also
        --------
        DataTree.sel
        Dataset.isel
        
xarray/core/datatree.py