title: Can't get rid of TypeError: 'str' object is not callable
body: <p>I'm trying to make/train a twitter sentiment analyser in ipython notebook and am having serious problems with one section of code:</p>
  
  <pre><code>import csv
  
  #Read the tweets one by one and process it
  inpTweets = csv.reader(open('SampleTweets.csv', 'rb'), delimiter=',',    quotechar='|')
  tweets = []
   for row in inpTweets:
      sentiment = row[0]
      tweet = row[1]
      processedTweet = processTweet(tweet)
      featureVector = getFeatureVector(processedTweet, stopwords)
      tweets.append((featureVector, sentiment));
  #end loop
  </code></pre>
  
  <p>And I'm getting this error:</p>
  
  <hr>
  
  <pre><code>TypeError                                 Traceback (most recent call last)
  &lt;ipython-input-10-bbcb1b9f05f4&gt; in &lt;module&gt;()
        7     sentiment = row[0]
        8     tweet = row[1]
  ----&gt; 9     processedTweet = processTweet(tweet)
       10     featureVector = getFeatureVector(processedTweet, stopwords)
       11     tweets.append((featureVector, sentiment));
  
  TypeError: 'str' object is not callable
  </code></pre>
  
  <p>And help would be seriously great, thanks!</p>