docs: 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>"