title: Get argument from Dropdown menu of Notebook
body: <p>I create a 'dropdown' menu in the notebook and tried to use it to update the graph from display function.</p>
  
  <p>I can use it in the filter function.</p>
  
  <pre class="lang-py prettyprint-override"><code>display(df.filter(df.year == getArgument("Year"))
  </code></pre>
  
  <p>However, when I tried to use it in the select statement, it started to not work.</p>
  
  <pre class="lang-py prettyprint-override"><code>display(df.select(getArgument("Year"))
  </code></pre>
  
  <p>Do you know why?</p>