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 step_impl(context, user_names_str):
    if not hasattr(context, 'users'):
        context.users = {}

    user_names = [name.strip() for name in re.split('and|,', user_names_str)]
    for user_name in user_names:
        token = 'fake_token_' + user_name
        user_id = context.helpers.create_test_user(user_name, token)
        context.users[user_name] = {'token': token, 'id': user_id}