Twitter API is used to extract the tweets during the Demonetization period in India i.e from November to December 2016
For more info, please refer https://www.nltk.org/api/nltk.sentiment.html
Hutto, C.J. & Gilbert, E.E. (2014). VADER: A Parsimonious Rule-based Model for Sentiment Analysis of Social Media Text. Eighth International Conference on Weblogs and Social Media (ICWSM-14). Ann Arbor, MI, June 2014.