title: Flattening list of lists
body: <p>Hey I am having trouble trying to make a list of list into just one please help:</p>
  
  <p>I want:</p>
  
  <pre><code>a = [['a'], 'b', 'c', 'd', 'e']
  </code></pre>
  
  <p>To become:</p>
  
  <pre><code>a = ['a', 'b', 'c', 'd', 'e']
  </code></pre>
  
  <p>Thanks</p>