code: def _duplicate_queries(self, 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
docs: Appends the most common duplicate queries to the given output.