title: Grouping lines with XlsxWriter
body: <p>I'm writing an Excel file with Python and XlsxWriter in which I'd like to group elements in 2 levels. Several 'boards' contain elements grouped by 'list'. I'd like to group all elements of the same 'list' and all the elements of the 'board' together.</p>
  
  <p>After many attempts I did not succeed in getting the following result:</p>
  
  <p><a href="https://i.stack.imgur.com/Xid0I.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Xid0I.png" alt="Excel example of expected result"></a></p>
  
  <p>Can someone help me understand how the function below works:</p>
  
  <pre><code>worksheet.set_row(1, None, None, {'level': 1})
  </code></pre>
  
  <p>I've followed the <a href="http://xlsxwriter.readthedocs.io/example_outline1.html#ex-outline1" rel="nofollow noreferrer">example</a> given in the documentation but I don't know what level to set on each line to have 2 grouping levels working as expected.</p>