code: public void updateNamespaces(Document document) {
  	Namespace rootNamespace = Namespace.gatherNamespaces(document);
  	document.setNamespace(rootNamespace);
  	for (org.openprovenance.prov.model.Bundle bu: utils.getBundle(document)) {
  	    Namespace ns=bu.getNamespace();
  	    if (ns!=null) {
  		ns.setParent(rootNamespace);
  	    } else {
  		ns=new Namespace();
  		ns.setParent(rootNamespace);
  		bu.setNamespace(ns);
  	    }
  	}
      }
docs: After reading a document, this method should be called to ensure that Namespaces are properly chained.
  @param document a {@link Document} to update