title: How to set the initial size of a QTreeView in a QSplitter?
body: <p>I have a <code>QTreeView</code> inside of a <code>QSplitter</code> that I want to set the initial size of. I have found that I can set both <code>setMinimumWidth(val)</code> and <code>setFixedWidth(val)</code> on the <code>QTreeView</code>, but neither of those seem to do what I need.</p>
  
  <p>The <code>setMinimumWidth(val)</code> only prevents the <code>QTreeView</code> from getting smaller than the value of <code>val</code>, and <code>setFixedWidth</code> prevents the user from resizing the <code>QTreeView</code> entirely.</p>
  
  <p>Is there anyway to set the initial size, either by setting <code>QSplitter</code> or setting <code>QTreeView</code>? I assume I need to set the <code>sizeHint</code>, but I'm not quite sure.</p>
  
  <p>I'm using Python 3 with PyQt5</p>