'Advance the cursor.'

def next(self):

    if self.__empty:
        raise StopIteration
    if (len(self.__data) or self._refresh()):
        if self.__manipulate:
            _db = self.__collection.database
            return _db._fix_outgoing(self.__data.popleft(), self.__collection)
        else:
            return self.__data.popleft()
    else:
        raise StopIteration
