code: def next_tokens_in_sequence(observed, current):
      
      idx = 0
      for word in current:
          if observed[idx:].count(word) != 0:
              found_pos = observed.index(word, idx)
              idx = max(idx + 1, found_pos)
          # otherwise, don't increment idx
      if idx < len(observed):
          return observed[idx:]
      else:
          return []
docs: Given the observed list of tokens, and the current list,
      finds out what should be next next emitted word