broken groovy

changeModel.groovy

import groovy.xml.XmlUtil

@Grab('com.yourmediashelf.fedora.client:fedora-client-core:0.7')

import static com.yourmediashelf.fedora.client.FedoraClient.*;
import com.yourmediashelf.fedora.client.*
import com.yourmediashelf.fedora.client.response.*
import com.yourmediashelf.fedora.client.request.*

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.CharacterData;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

FedoraCredentials credentials = new FedoraCredentials("http://fedoratest.mzk.cz/fedora", "fedoraAdmin", "fedoraAdmin");
FedoraClient fedora = new FedoraClient(credentials);
FedoraRequest.setDefaultClient(fedora);

FedoraResponse response = getDatastreamDissemination("uuid:530719f5-ee95-4449-8ce7-12b0f4cadb22", "DC").execute();
String xmlString = response.getEntity(String.class);

/*
Node editedXml = new XmlParser().parseText(xmlString)
editedXml.'dc:type'.replaceNode {
    'dc:type'('model:sheetmusic')
}

StringWriter stringWriter = new StringWriter()
XmlNodePrinter nodePrinter = new XmlNodePrinter(new PrintWriter(stringWriter));
nodePrinter.setPreserveWhitespace(true);
nodePrinter.print(editedXml);

String editedXmlString = stringWriter.toString();
println(editedXmlString);
*/

DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.parse(new StringReader(xmlString));

//Node dcType = doc.getElementsByTagName("dc:type").item(0);
//dcType.setTextContent("model:sheetmusic");

//System.out.println("Title: " + getCharacterDataFromElement(doc));

//modifyDatastream("uuid:530719f5-ee95-4449-8ce7-12b0f4cadb22", "DC").content(editedXmlString).execute();