title: Unpack list of lists into list
body: <p>I have list of lists of tuples:</p>
  
  <pre><code>a = [[(1, 2), (3, 4), (5, 6)], [(7, 8), (9, 10)]]
  </code></pre>
  
  <p>How can I make one list of tuples:</p>
  
  <pre><code>b = [(1, 2), (3, 4), (5, 6), (7, 8), (9, 10)]
  </code></pre>
  
  <p>Naive way is:</p>
  
  <pre><code>b = []
  for c in a:
      for t in c:
          b.append(t)
  </code></pre>
  
  <p>List comprehension or any other ideas are welcome.</p>