title: module 'sklearn' has no attribute 'cross_validation'
body: <p>I am trying to split my dataset into training and testing dataset, but I am getting this error:</p>
  
  <pre><code>X_train,X_test,Y_train,Y_test = sklearn.cross_validation.train_test_split(X,df1['ENTRIESn_hourly'])
  </code></pre>
  
  <hr>
  
  <pre><code>AttributeError                            Traceback (most recent call last)
  &lt;ipython-input-53-5445dab94861&gt; in &lt;module&gt;()
  ----&gt; 1 X_train,X_test,Y_train,Y_test = sklearn.cross_validation.train_test_split(X,df1['ENTRIESn_hourly'])
  
  AttributeError: module 'sklearn' has no attribute 'cross_validation'
  </code></pre>
  
  <p>How can I handle this?</p>