code: def xml(self):
          
          xml = []
          xml.append('<?xml version="1.0" encoding="%s"?>' % XML_ENCODING.get(self.encoding, self.encoding))
          xml.append("<%s>" % XML_TEXT)
          xml.extend([sentence.xml for sentence in self])
          xml.append("</%s>" % XML_TEXT)
          return "\n".join(xml)
docs: Yields the sentence as an XML-formatted string (plain bytestring, UTF-8 encoded).
              All the sentences in the XML are wrapped in a <text> element.