title: I use python 3.6 and i want to make sentiment analysis but i have an error in nltk.metrics package?
body: <p>i write the code as here : </p>
  
  <pre><code>    print ('pos precision:', nltk.metrics.precision(refsets['pos'], 
      testsets['pos']))
      print ('pos recall:', nltk.metrics.recall(refsets['pos'], 
      testsets['pos']))
  </code></pre>
  
  <p>and the output as here : </p>
  
  <pre><code>   line 35, in evaluate_classifier
     print ('pos precision:', nltk.metrics.precision(refsets['pos'], 
     testsets['pos']))
     AttributeError: module 'nltk.translate.metrics' has no attribute 
    'precision'
  </code></pre>
  
  <p>How can i solve this error ? </p>