如何使用sentiwordnet获取synet的得分名称

Question

我有一个字符串，我希望使用sentiword网得到每个单词的pos / neg分数。这是我的代码：

from nltk.corpus import sentiwordnet as swn
from nltk.tokenize import word_tokenize

text = "good bad. work hard"
word_tokens = word_tokenize(text)
for i in word_tokens:
     synsets=list(swn.senti_synsets(i))
     print(synsets[0])

我的输出有错误：

<good.n.01: PosScore=0.5 NegScore=0.0>
<bad.n.01: PosScore=0.0 NegScore=0.875>
Traceback (most recent call last):
  File "C:\Python34\test2.py", line 20, in <module>
    print(synsets[0])
IndexError: list index out of range

任何想法为什么？ 提前致谢