def time_diff(t0, t1):
    """
    Args:
        :t0: start time in seconds
        :t1: end time in seconds
    Returns: string with time difference (i.e. t1-t0)
    """
    minutes, seconds = divmod(t1 - t0, 60)
    hours, minutes = divmod(minutes, 60)
    return "%d hours, %d minutes, %d seconds" % (hours, minutes, seconds)