def METHOD_NAME():
    from .. import get_fs, register_filesystem
    from ..fsspec_adapter import FsSpecAdapter
    class InMemoryFileSystemAdapter(FsSpecAdapter):
        def __init__(self, **kwargs):
            super().__init__("memory", **kwargs)
    register_filesystem("memory", InMemoryFileSystemAdapter)
    assert isinstance(get_fs("file://"), LocalFileSystem)
    assert isinstance(get_fs("memory://"), InMemoryFileSystemAdapter)
    try:
        get_fs("unknown://")
    except ValueError as e:
        assert "Unknown file system type" in e.__str__()