Changes to vistweet.ipynb

[DavidQuartey]

Hello @yabebalFantaye , want to suggest changes to vistweet.ipynb as part of the Twitter project.

I realised print 'saved numbers of tweets: ', len(tweets_data) should instead be print ('saved numbers of tweets: ', len(tweets_data)).

[10acad]

@DavidQuartey. Thank you for the suggestion. Yes, your suggestion if relevant for the notebook to work with Python 3.

[DavidQuartey]

@10acad Does that mean the notebook was coded in Python 2?