'Stream the next set of ticker sentiment values into
SentimentEvent objects.'

def stream_next(self, stream_date=None):

    if (stream_date is not None):
        stream_date_str = stream_date.strftime('%Y-%m-%d')
        date_df = self.sent_df.ix[stream_date_str:stream_date_str]
        for row in date_df.iterrows():
            sev = SentimentEvent(stream_date, row[1]['Ticker'], row[1]['Sentiment'])
            self.events_queue.put(sev)
    else:
        print 'No    stream_date    provided    for    stream_next    sentiment    event!'
