def _refresh(self):
        if len(self.__data) or self.__killed:
            return len(self.__data)

        if self.__id:  # Get More
            self.__send_message(
                message.get_more(self.__collection.full_name,
                                 self.__batch_size, self.__id))

        else:  # Cursor id is zero nothing else to return
            self.__killed = True

        return len(self.__data)
Refreshes the cursor with more data from the server.
dataset/ETHPy150Open blynch/CloudMemeBackend/pymongo/command_cursor.py/CommandCursor._refresh