def open_datatree(
    name: str,
    cache: bool = True,
    cache_dir: None | str | os.PathLike = None,
    *,
    engine: T_Engine = None,
    **kws,
) -> DataTree:
    """
    Open a dataset as a `DataTree` from the online repository (requires internet).

    If a local copy is found then always use that to avoid network traffic.

    Available datasets:

    * ``"imerghh_730"``: GPM IMERG Final Precipitation L3 Half Hourly 0.1 degree x 0.1 degree V07 from 2021-08-29T07:30:00.000Z
    * ``"imerghh_830"``: GPM IMERG Final Precipitation L3 Half Hourly 0.1 degree x 0.1 degree V07 from 2021-08-29T08:30:00.000Z
    * ``"air_temperature"``: NCEP reanalysis subset
    * ``"air_temperature_gradient"``: NCEP reanalysis subset with approximate x,y gradients
    * ``"basin_mask"``: Dataset with ocean basins marked using integers
    * ``"ASE_ice_velocity"``: MEaSUREs InSAR-Based Ice Velocity of the Amundsen Sea Embayment, Antarctica, Version 1
    * ``"rasm"``: Output of the Regional Arctic System Model (RASM)
    * ``"ROMS_example"``: Regional Ocean Model System (ROMS) output
    * ``"tiny"``: small synthetic dataset with a 1D data variable
    * ``"era5-2mt-2019-03-uk.grib"``: ERA5 temperature data over the UK
    * ``"eraint_uvz"``: data from ERA-Interim reanalysis, monthly averages of upper level data
    * ``"ersstv5"``: NOAA's Extended Reconstructed Sea Surface Temperature monthly averages

    Parameters
    ----------
    name : str
        Name of the file containing the dataset.
        e.g. 'air_temperature'
    cache_dir : path-like, optional
        The directory in which to search for and write cached data.
    cache : bool, optional
        If True, then cache data locally for use on subsequent calls
    **kws : dict, optional
        Passed to xarray.open_dataset

    See Also
    --------
    tutorial.load_datatree
    open_datatree
    """
    try:
        import pooch
    except ImportError as e:
        raise ImportError(
            "tutorial.open_dataset depends on pooch to download and manage datasets."
            " To proceed please install pooch."
        ) from e

    logger = pooch.get_logger()
    logger.setLevel("WARNING")

    cache_dir = _construct_cache_dir(cache_dir)
    if name in external_urls:
        url = external_urls[name]
    else:
        path = pathlib.Path(name)
        if not path.suffix:
            # process the name
            default_extension = ".nc"
            if engine is None:
                _check_netcdf_engine_installed(name)
            path = path.with_suffix(default_extension)
        elif path.suffix == ".grib":
            if engine is None:
                engine = "cfgrib"
                try:
                    import cfgrib  # noqa: F401
                except ImportError as e:
                    raise ImportError(
                        "Reading this tutorial dataset requires the cfgrib package."
                    ) from e

        url = f"{base_url}/raw/{version}/{path.name}"

    headers = {"User-Agent": f"xarray {sys.modules['xarray'].__version__}"}
    downloader = pooch.HTTPDownloader(headers=headers)

    # retrieve the file
    filepath = pooch.retrieve(
        url=url, known_hash=None, path=cache_dir, downloader=downloader
    )
    ds = _open_datatree(filepath, engine=engine, **kws)
    if not cache:
        ds = ds.load()
        pathlib.Path(filepath).unlink()

    return ds

    Open a dataset as a `DataTree` from the online repository (requires internet).

    If a local copy is found then always use that to avoid network traffic.

    Available datasets:

    * ``"imerghh_730"``: GPM IMERG Final Precipitation L3 Half Hourly 0.1 degree x 0.1 degree V07 from 2021-08-29T07:30:00.000Z
    * ``"imerghh_830"``: GPM IMERG Final Precipitation L3 Half Hourly 0.1 degree x 0.1 degree V07 from 2021-08-29T08:30:00.000Z
    * ``"air_temperature"``: NCEP reanalysis subset
    * ``"air_temperature_gradient"``: NCEP reanalysis subset with approximate x,y gradients
    * ``"basin_mask"``: Dataset with ocean basins marked using integers
    * ``"ASE_ice_velocity"``: MEaSUREs InSAR-Based Ice Velocity of the Amundsen Sea Embayment, Antarctica, Version 1
    * ``"rasm"``: Output of the Regional Arctic System Model (RASM)
    * ``"ROMS_example"``: Regional Ocean Model System (ROMS) output
    * ``"tiny"``: small synthetic dataset with a 1D data variable
    * ``"era5-2mt-2019-03-uk.grib"``: ERA5 temperature data over the UK
    * ``"eraint_uvz"``: data from ERA-Interim reanalysis, monthly averages of upper level data
    * ``"ersstv5"``: NOAA's Extended Reconstructed Sea Surface Temperature monthly averages

    Parameters
    ----------
    name : str
        Name of the file containing the dataset.
        e.g. 'air_temperature'
    cache_dir : path-like, optional
        The directory in which to search for and write cached data.
    cache : bool, optional
        If True, then cache data locally for use on subsequent calls
    **kws : dict, optional
        Passed to xarray.open_dataset

    See Also
    --------
    tutorial.load_datatree
    open_datatree
    
xarray/tutorial.py