title: Convert Python dictionary to Spark DataFrame
body: <p>I have a Python dictionary :</p>
  
  <pre><code>dic = {
         (u'aaa',u'bbb',u'ccc'):((0.3, 1.2, 1.3, 1.5), 1.4, 1),
         (u'kkk',u'ggg',u'ccc',u'sss'):((0.6, 1.2, 1.7, 1.5), 1.4, 2)
         }
  </code></pre>
  
  <p>I'd like to convert this dictionary to Spark DataFrame with columns :</p>
  
  <p><code>['key', 'val_1', 'val_2', 'val_3', 'val_4', 'val_5', 'val_6']</code></p>
  
  <p>example row (1) :</p>
  
  <p><code>key                  | val_1   |val_2 | val_3 | val_4  | val_5| val_6|</code></p>
  
  <p><code>u'aaa',u'bbb',u'ccc' | 0.3     |1.2   |1.3    |1.5     |1.4   |1     |</code></p>
  
  <p>Thank you in advance</p>