:return: The next result item.
        :rtype: dict 
        :raises StopIteration: If there is no more result.

def next(self):
        """
        :return: The next result item.
        :rtype: dict 
        :raises StopIteration: If there is no more result.
            
        """
        if self._cur_item is not None:
            res = self._cur_item
            self._cur_item = None
            return res
        
        return next(self._ex_context)