title: Cannot import cross_validation from sklearn in Python2
body: <p>I get the following error when I run bash: </p>
  
  <pre><code>shryanss-mbp-2:Desktop shryansgoyal$ python trash.py
  Traceback (most recent call last):
    File "trash.py", line 15, in &lt;module&gt;
      import sklearn.cross_validation as cross_validation
  ImportError: No module named cross_validation
  </code></pre>
  
  <p>What could be the cause?</p>