XML Transformation using XSLT

public static XmlElement Transfomer(string xsltFilePath, XmlDocument bericht)
        {
            XslCompiledTransform transformer = new XslCompiledTransform();
            XsltSettings xsltSettings = new XsltSettings(false, true);
            transformer.Load(xsltFilePath, xsltSettings, new XmlUrlResolver());



            XmlDocument transformedMessage = new XmlDocument();

            using (MemoryStream memoryStream = new MemoryStream())
            {
                XmlWriterSettings writerSettings = new XmlWriterSettings();
                writerSettings.Indent = true;
                writerSettings.IndentChars = "\t";
                writerSettings.Encoding = System.Text.Encoding.UTF8;
                writerSettings.ConformanceLevel = ConformanceLevel.Fragment;
                writerSettings.OmitXmlDeclaration = true;

                XmlWriter writer = XmlWriter.Create(memoryStream, writerSettings);

                transformer.Transform(bericht, writer);
                writer.Flush();
                memoryStream.Position = 0;
                transformedMessage.Load(memoryStream);
            }

            return transformedMessage.DocumentElement;
        }