docs: def next_tuple(self):
          """Next tuple steps:
  
          1. Emit (term, timestamp) for next term in sequence w/current UTC time.
          """
          term = next(self.term_seq)
          timestamp = datetime.datetime.utcnow().isoformat()
          self.emit([term, timestamp], tup_id=self.pack_tup_id(term, timestamp))