我正在尝试使用教程http://streamhacker.com/2008/12/29/how-to-train-a-nltk-chunker/
训练我自己的NLTK chunker我把代码编写为，
Eclipse-RegisterBuddy但是在这里，我收到了错误，
>>> import nltk
>>> import nltk.chunk
>>> def conll_tag_chunks(chunk_sents):
tag_sents = [nltk.chunk.tree2conlltags(tree) for tree in chunk_sents]
return [[(t, c) for (w, t, c) in chunk_tags] for chunk_tags in tag_sents]
>>> import nltk.corpus, nltk.tag
>>> from nltk.metrics import accuracy
>>> def ubt_conll_chunk_accuracy(train_sents, test_sents):
train_chunks = conll_tag_chunks(train_sents)
test_chunks = conll_tag_chunks(test_sents)
u_chunker = nltk.tag.UnigramTagger(train_chunks)
print 'u:', accuracy(u_chunker, test_chunks)
ub_chunker = nltk.tag.BigramTagger(train_chunks, backoff=u_chunker)
print 'ub:', accuracy(ub_chunker, test_chunks)
ubt_chunker = nltk.tag.TrigramTagger(train_chunks, backoff=ub_chunker)
print 'ubt:', accuracy(ubt_chunker, test_chunks)
ut_chunker = nltk.tag.TrigramTagger(train_chunks, backoff=u_chunker)
print 'ut:', accuracy(ut_chunker, test_chunks)
utb_chunker = nltk.tag.BigramTagger(train_chunks, backoff=ut_chunker)
print 'utb:', accuracy(utb_chunker, test_chunks)
>>> conll_train = nltk.corpus.conll2000.chunked_sents('train.txt')
>>> conll_test = nltk.corpus.conll2000.chunked_sents('test.txt')
>>> ubt_conll_chunk_accuracy(conll_train, conll_test)
如果有人可能会建议，我该如何解决此错误？提前致谢。 我在MS-Windows 10上使用NLTK 3.1，Python2.7.11。