How to use the fsspec.mapping.FSMap function in fsspec

def test_path_or_store_write_to_bucket(self):
        path, _, _ = _get_path_or_store('http://obs.eu-de.otc.t-systems.com/fake_bucket/fake_cube.zarr',
                                        mode='write',
                                        client_kwargs={'aws_access_key_id': 'some_fake_id',
                                                       'aws_secret_access_key': 'some_fake_key'})
        self.assertIsInstance(path, fsspec.mapping.FSMap)

def test_path_or_store_read_from_bucket(self):
        path, _, _ = _get_path_or_store('http://obs.eu-de.otc.t-systems.com/dcs4cop-obs-02/OLCI-SNS-RAW-CUBE-2.zarr',
                                        mode='read')
        self.assertIsInstance(path, fsspec.mapping.FSMap)

url: str
        Root URL of mapping
    check: bool
        Whether to attempt to read from the location before instantiation, to
        check that the mapping does exist
    create: bool
        Whether to make the directory corresponding to the root before
        instantiating

    Returns
    -------
    ``FSMap`` instance, the dict-like key-value store.
    """
    # Removing protocol here - could defer to each open() on the backend
    fs, urlpath = url_to_fs(url, **kwargs)
    return FSMap(urlpath, fs, check, create)

def get_mapper(self, root, check=False, create=False):
        """Create key/value store based on this file-system

        Makes a MutibleMapping interface to the FS at the given root path.
        See ``fsspec.mapping.FSMap`` for further details.
        """
        from .mapping import FSMap

        return FSMap(root, self, check, create)

def _open_asset(path, data_format, zarr_kwargs, cdf_kwargs, preprocess, varname):
    protocol = None
    root = path
    if isinstance(path, fsspec.mapping.FSMap):
        protocol = path.fs.protocol
        if isinstance(protocol, list):
            protocol = tuple(protocol)

        if protocol in {'http', 'https', 'file'} or protocol is None:
            path = path.root
            root = path

        else:
            root = path.root

    if data_format == 'zarr':
        logger.debug(f'Opening zarr store: {root} - protocol: {protocol}')
        try:
            ds = xr.open_zarr(path, **zarr_kwargs)
        except Exception as e: