code: def start_serialization(self):
          
          if (self.root):
              self.xml = XmlPrinter(self.stream, self.options.get("encoding", settings.DEFAULT_CHARSET))
              self.xml.startDocument()
              self.xml.startElement("django-objects", {"version" : "1.0"})
docs: Start serialization -- open the XML document and the root element.