code: def merge(self, dest, *others):
          
          items = [self.key]
          items.extend([other.key for other in others])
          self.database.pfmerge(dest, *items)
          return HyperLogLog(self.database, dest)
docs: Merge one or more :py:class:`HyperLogLog` instances.
  
          :param dest: Key to store merged result.
          :param others: One or more ``HyperLogLog`` instances.