title: nltk.word_tokenize() giving AttributeError: 'module' object has no attribute 'defaultdict'
body: <p>I am new to nltk.
  I was trying some basics.</p>
  
  <pre><code>import nltk
  nltk.word_tokenize("Tokenize me")
  </code></pre>
  
  <p>gives me this following error</p>
  
  <pre><code>Traceback (most recent call last):
  File "&lt;pyshell#27&gt;", line 1, in &lt;module&gt;
  nltk.word_tokenize("hi im no onee")
  File "C:\Python27\lib\site-packages\nltk\tokenize\__init__.py", line 101, in word_tokenize
  return [token for sent in sent_tokenize(text, language)
  File "C:\Python27\lib\site-packages\nltk\tokenize\__init__.py", line 85, in sent_tokenize
  tokenizer = load('tokenizers/punkt/{0}.pickle'.format(language))
  File "C:\Python27\lib\site-packages\nltk\data.py", line 786, in load
  resource_val = pickle.load(opened_resource)
  AttributeError: 'module' object has no attribute 'defaultdict'
  </code></pre>
  
  <p>Please someone help. Please tell me how to fix this error.</p>