Task: Calculate the sentiment intensity or valence score of the tweet, which should be a real number between 0 (extremely negative) and 1 (extremely positive).
Tweet: What terrible thing to see and have no vision-\n\nHelen Keller-\n\n-Begin with the end in mind-\n\nStephen Covey-\n\n #whereareugoing
Intensity score: 
0.426