title: Nested list to dict
body: <p>I am trying to create <code>dict</code> by nested <code>list</code>:</p>
  
  <pre><code>groups = [['Group1', 'A', 'B'], ['Group2', 'C', 'D']]
  
  L = [{y:x[0] for y in x if y != x[0]} for x in groups]
  d = { k: v for d in L for k, v in d.items()}
  
  print (d)
  {'B': 'Group1', 'C': 'Group2', 'D': 'Group2', 'A': 'Group1'}
  </code></pre>
  
  <p>But it seems a bit complicated.</p>
  
  <p>Is there a better solution?</p>