public double?ExtractSpeedFromHtml(string html_document_2) { if (html_document_2.Contains("Error - VesselFinder")) { return(null); } string node = _creator.CreatePrepareAndVerifyRowNodeString(html_document_2); string speed = _stringParser.GetTrimmedSpeed(node); return(_stringParser.ParsedTrimmedNullableDouble(speed)); }