def format_walk_time(walk_time):
    """
    takes argument: float walkTime in seconds
    returns argument: string time  "xx minutes xx seconds"
    """
    if walk_time > 0.0:
        return str(int(walk_time / 60.0)) + " minutes " + str(int(round(walk_time % 60))) + " seconds"
    else:
        return "Walk time is less than zero! something is wrong"