title: Sentiment analysis for sentences- positive, negative and neutral
body: <p>I'm designing a text classifier in Python using NLTK. One of the features considered in every sentence is it's sentiment. I want to weight sentences with either positive or negative sentiments more that those without any sentiment(neutral sentences). Using the movie review corpus along with the naive bayes classifier results in only positive and negative labels. I tried using demo_liu_hu_lexicon in nltk.sentiment.utils but the function does not return any values but instead prints it to the output and is very slow. Does anyone know of a library which gives some sort of weight to sentences based on sentiment?</p>
  
  <p>Thanks!</p>