public double?ExtractCourseFromHtml(string html_document_2)
        {
            if (html_document_2.Contains("Error - VesselFinder"))
            {
                return(null);
            }
            string node   = _creator.CreatePrepareAndVerifyRowNodeString(html_document_2);
            string course = _stringParser.GetTrimmedCourse(node);

            return(_stringParser.ParsedTrimmedNullableDouble(course));
        }