code: def decode_link(self, link):
          
  
          if link.HasField("bucket"):
              bucket = bytes_to_str(link.bucket)
          else:
              bucket = None
          if link.HasField("key"):
              key = bytes_to_str(link.key)
          else:
              key = None
          if link.HasField("tag"):
              tag = bytes_to_str(link.tag)
          else:
              tag = None
  
          return (bucket, key, tag)
docs: Decodes an RpbLink message into a tuple
  
          :param link: an RpbLink message
          :type link: riak.pb.riak_pb2.RpbLink
          :rtype tuple