def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def refresh(self):
        """refreshes the Gtk.Liststore"""
        self.backendid_to_iter = {}
        self.liststore.clear()

        # Sort backends
        # 1, put default backend on top
        # 2, sort backends by human name
        backends = list(self.req.get_all_backends(disabled=True))
        backends = sorted(backends,
                          key=lambda backend: (not backend.is_default(),
                                               backend.get_human_name()))

        for backend in backends:
            self.add_backend(backend)
            self.on_backend_state_changed(None, backend.get_id())