def str_format_timedelta(timedelta_object):
    """Return formatted and trimmed timedelta object.

    Args:
        timedelta_object (timedelta): Datetime.timedelta object.

    Returns:
        Str of timedelta object formatted HH:MM:SS.
    """
    trimmed = str(timedelta_object).split('.')[0]
    if len(trimmed) == 7:
        return '0{}'.format(trimmed)
    return trimmed