public string Handle(Process[] processes) {
     var xmlBuilder = new StringBuilder();
     var xmlWriter = XmlWriter.Create(xmlBuilder, new XmlWriterSettings() { ConformanceLevel = ConformanceLevel.Fragment });
     foreach (var rows in processes.Select(p => p.Results)) {
         foreach (var row in rows) {
             xmlWriter.WriteStartElement("add");
             foreach (var column in row.Columns) {
                 xmlWriter.WriteAttributeString(column, row[column].ToString());
             }
             xmlWriter.WriteEndElement(); //add
         }
     }
     xmlWriter.Flush();
     return xmlBuilder.ToString();
 }