ImportError: No module named model_selection : <p>I am trying to use <code>train_test_split</code> function and write:</p>

<pre><code>from sklearn.model_selection import train_test_split
</code></pre>

<p>and this causes </p>

<pre><code>ImportError: No module named model_selection
</code></pre>

<p>Why? And how to overcome?</p>
