def public(fun, scope=None):
    """
    Functions that allow any client access, including those that haven't logged
    in should be wrapped in this decorator.

    :param fun: A REST endpoint.
    :type fun: callable
    :param scope: The scope or list of scopes required for this token.
    :type scope: str or list of str or None
    """
    fun.accessLevel = 'public'
    fun.requiredScopes = scope
    return fun