This will convert the timestamp to datetime, add the timedelta
        and then return it as a timestamp
    :param timestamp:    str of the date and time
    :param time_delta:   datetime.timedelta of the time to add
    :param str_format:   str of the format of the timestamp
    :return:             str of the new timestamp

def add_to_timestamp(timestamp, time_delta,
                     str_format='%Y-%m-%d_%H:%M:%S.fff'):
    """
        This will convert the timestamp to datetime, add the timedelta
        and then return it as a timestamp
    :param timestamp:    str of the date and time
    :param time_delta:   datetime.timedelta of the time to add
    :param str_format:   str of the format of the timestamp
    :return:             str of the new timestamp
    """
    date_time = str_to_datetime(timestamp, str_format) + time_delta
    return datetime_to_str(timestamp, str_format)