title: list.append() doesn't keep shuffled values
body: <p>I have the following code:</p>
  <pre><code>list =[] 
  list1 = ['Dublin', 'Kiev', 'Warsaw', 'Moscow']
  
  for i in range(3):
      random.shuffle(list1)
      list.append(list1) 
  list
  </code></pre>
  <p>However, the output keeps the last shuffled value as:</p>
  <pre><code>[['Dublin', 'Moscow', 'Kiev', 'Warsaw'],
   ['Dublin', 'Moscow', 'Kiev', 'Warsaw'],
   ['Dublin', 'Moscow', 'Kiev', 'Warsaw']]
  </code></pre>
  <p>I'm really not sure what's happening, and why it behaves this way.
  Appreciate any replies.</p>