@classmethod
    def normpath(cls, path):
        if not path:
            raise ValueError("This filesystem can only normalize paths"
                             " that are not empty")
        if not path.startswith(cls.root_path):
            raise ValueError("This filesystem can only normalize"
                             " paths that start with %s: '%s' is not"
                             " valid" % (cls.root_path, path))
        return pp.normpath(path)

    #: Split a pathname into a tuple of ``(head, tail)``.
Return a normalized absolutized version of the pathname path.
dataset/ETHPy150Open openstack/taskflow/taskflow/persistence/backends/impl_memory.py/FakeFilesystem.normpath