stock_sentiment library Null safety


Headline class date: the date of the headline text: the text of the headline link: the link to the article of the headline
SentimentResult class average: the average of headlines sentiment for the day positive: how many positive sentiments for the day negative: how many negative sentiments for the day neutral: how many neutral sentiments for the day
StockSentiment class initialized with String ticker ticker is a space seperated string with different stock tickers