code: def _summary(self, name=None):
          
          if len(self) > 0:
              head = self[0]
              if hasattr(head, 'format') and not isinstance(head, str):
                  head = head.format()
              tail = self[-1]
              if hasattr(tail, 'format') and not isinstance(tail, str):
                  tail = tail.format()
              index_summary = ', %s to %s' % (pprint_thing(head),
                                              pprint_thing(tail))
          else:
              index_summary = ''
  
          if name is None:
              name = type(self).__name__
          return '%s: %s entries%s' % (name, len(self), index_summary)
docs: Return a summarized representation.
  
          Parameters
          ----------
          name : str
              name to use in the summary representation
  
          Returns
          -------
          String with a summarized representation of the index