title: Why does the append method return None with my list?
body: <p>I know I can use "append()" to add an element to a list, but why does the assignment return None?</p>
  
  <pre><code>&gt;&gt;&gt; a=[1,2,3]
  &gt;&gt;&gt; a.append(4)
  &gt;&gt;&gt; print a 
  [1, 2, 3, 4]
  &gt;&gt;&gt; a=a.append(5)
  &gt;&gt;&gt; print a 
  None
  &gt;&gt;&gt;
  </code></pre>