for a news item(news.headlines.Definition("R:AMD.O AND Language:LEN AND Source:RTRS").get_data()), does {"_qcode": "R:AMD.O"} appear only once, or can a single news item contain multiple {"_qcode": "R:..."} values? For example, is it possible for one news article to include both {"_qcode": "R:AMD.O"} and {"_qcode": "R:INTC.O"}?