title: How to export/duplicate object to existing maya file
body: <p>I have a Maya object which I want to export into an <strong>existing</strong> Maya file.</p>
  
  <p>I know that I can export a selected object into a new Maya file.</p>
  
  <pre><code>cmds.file('filename', type='mayaBinary', exportSelected=True)
  </code></pre>
  
  <p>but I want to export into an existing one.</p>
  
  <p>How can I do that?</p>