code: def last(self):
          
          if len(self):
              self._params.update(limit=1)
              if 'filter' not in self._params:
                  return list(self)[-1]
              else: # Filter may not return results
                  result = list(self)
                  if result:
                      return result[-1]
docs: Returns the last object matched or None if there is no
          matching object.
          ::
                  
              >>> iterator = Host.objects.iterator()
              >>> c = iterator.filter('kali')
              >>> if c.exists():
              >>>    print(c.last())
              Host(name=kali-foo)
          
          :return: element or None