SBMLDocument sbmlDoc = new SBMLDocument(3, 1);
sbmlDoc.addDeclaredNamespace("xmlns:html", "http://www.w3.org/1999/xhtml");
sbmlDoc.addNamespace("ns1", "xmlns", "http://www.test.com");
Model sbmlModel = sbmlDoc.createModel("test_model");
sbmlModel.addDeclaredNamespace("html", "http://www.w3.org/1999/xhtml");
sbmlModel.addDeclaredNamespace("ns1", "http://www.test.com");
// sbmlModel.addDeclaredNamespace("toto:ns2", "http://www.test.com");
sbmlModel.addDeclaredNamespace("xmlns:ns3", "http://www.test.com");
// but it is not working. In the output file written with: