title: I am getting TypeError: unhashable type: 'list', while trying to find the word frequency
body: <p>I am getting </p>
  
  <pre><code>TypeError: unhashable type: 'list'
  </code></pre>
  
  <p>when I am trying this piece of code:</p>
  
  <pre><code>from nltk import FreqDist
  fd = FreqDist()
  token_words = data['tweet_split'].apply(lambda tweet: tweet.split())
  for i in token_words:
  
   fd[i] += 1
  print(fd)
  </code></pre>