def xml(self, text=TEXT):
        """ Generate an XML output from the report data. """
        def convert(line):
            xml = "  <item>\n"
            for f in line.index:
                xml += "    <field name=\"%s\">%s</field>\n" % (f, line[f])
            xml += "  </item>\n"
            return xml
        return "<items>\n" + '\n'.join(self._data.apply(convert, axis=1)) + \
               "</items>"
Generate an XML output from the report data.