title: TypeError: unhashable type: 'dict'
body: <p>This piece of code is giving me an error <code>unhashable type: dict</code> can anyone explain to me what the solution is?</p>
  <pre><code>negids = movie_reviews.fileids('neg')
  def word_feats(words):
      return dict([(word, True) for word in words])
  
  negfeats = [(word_feats(movie_reviews.words(fileids=[f])), 'neg') for f in negids]
  stopset = set(stopwords.words('english'))
  
  def stopword_filtered_word_feats(words):
      return dict([(word, True) for word in words if word not in stopset])
  
  result=stopword_filtered_word_feats(negfeats)
  </code></pre>