def seconds_to_hms(seconds):
    """
    Converts second to the format "h:mm:ss"

    Args:
        seconds: number of seconds

    Returns:
        A string representing the seconds with the format "h:mm:ss". An empty string if seconds is None.
    """
    if seconds is None:
        return ""

    m, s = divmod(seconds, 60)
    h, m = divmod(m, 60)
    return "%d:%02d:%02d" % (h, m, s)