code: def next(self):
          
          if self._currentObject is None:
              raise StopIteration()
          nextPageToken = None
          if self._nextObject is not None:
              start = self._getStart(self._nextObject)
              # If start > the search anchor, move the search anchor. Otherwise,
              # increment the distance from the anchor.
              if start > self._searchAnchor:
                  self._searchAnchor = start
                  self._distanceFromAnchor = 0
              else:
                  self._distanceFromAnchor += 1
              nextPageToken = "{}:{}".format(
                  self._searchAnchor, self._distanceFromAnchor)
          ret = self._extractProtocolObject(self._currentObject), nextPageToken
          self._currentObject = self._nextObject
          self._nextObject = next(self._searchIterator, None)
          return ret
docs: Returns the next (object, nextPageToken) pair.