def _duplicate_queries(self, output):
        """Appends the most common duplicate queries to the given output."""
        if QC_SETTINGS['DISPLAY_DUPLICATES']:
            for query, count in self.queries.most_common(QC_SETTINGS['DISPLAY_DUPLICATES']):
                lines = ['\nRepeated {0} times.'.format(count)]
                lines += wrap(query)
                lines = "\n".join(lines) + "\n"
                output += self._colorize(lines, count)
        return output
Appends the most common duplicate queries to the given output.