code: def _print_refs(self, refs, total, prefix='    ',
                      level=1, minsize=0, minpct=0.1):
          
          lrefs = list(refs)
          lrefs.sort(key=lambda x: x.size)
          lrefs.reverse()
          for ref in lrefs:
              if ref.size > minsize and (ref.size*100.0/total) > minpct:
                  self.stream.write('%-50s %-14s %3d%% [%d]\n' % (
                      trunc(prefix+str(ref.name), 50),
                      pp(ref.size),
                      int(ref.size*100.0/total),
                      level
                  ))
                  self._print_refs(ref.refs, total, prefix=prefix+'  ',
                                   level=level+1)
docs: Print individual referents recursively.