title: Pandas - Concat multiindex with single index
body: <p>I have a dataframe that looks like this:</p>
  
  <pre><code>                Qty
  Year    Month
  2017    Jan     1
          Feb     2
  2016    Jan     7
          Feb     4
  </code></pre>
  
  <p>and <code>df.groupby(level = 0).sum()</code> gives me this:</p>
  
  <pre><code>        Qty
  Year
  2017    3
  2016    11
  </code></pre>
  
  <p>and I want to produce this:</p>
  
  <pre><code>                Qty
  Year    Month
  2017    Jan     1
          Feb     2
  2017 Total      3
  2016    Jan     7
          Feb     4
  2016 Total      11
  </code></pre>
  
  <p>Where the value of the  <code>Month</code> index is an empty string. <code>concat</code> doesn't quit work how I want, it gives:</p>
  
  <pre><code>               Qty
  (2017, Jan)    1
  (2017, Feb)    2
  (2016, Jan)    7
  (2016, Feb)    4
  2017           3
  2016           11
  </code></pre>