title: Updating OrderedDict getting None
body: <p>Here is my list ,</p>
  
  <pre><code>z=[OrderedDict([('name', 'abc'), ('lastname', 'lastname.'), ('address', 'Mumbai'), ('cell', '21******')]), OrderedDict([('name', 'abc'), ('lastname', 'lastname.'), ('address', 'Mumbai'), ('cell', '21******')]), OrderedDict([('name', 'xyz'), ('lastname', 'lastnamexyz.'), ('address', 'Heaven'), ('cell', '2156******')])]
  </code></pre>
  
  <p>I am trying to change keys of this dictionary , </p>
  
  <p>What i am trying ,</p>
  
  <pre><code>&gt;&gt;&gt; temp_lst=[]
  &gt;&gt;&gt; for i in z:
      newo=OrderedDict()
      temp_lst.append(newo.update(Name=i.get('name'),Lastname=i.get('lastname')))
  &gt;&gt;&gt; print temp_lst
      [None, None, None]
  </code></pre>
  
  <p>This code is printing tmp_lst as <code>[None, None, None]</code></p>
  
  <p>But when i have tried following , got the correct result.</p>
  
  <pre><code>&gt;&gt;&gt; for i in z:
      newo=OrderedDict()
      newo.update(Name=i.get('name'),Lastname=i.get('lastname'))
      temp_lst.append(newo)   
  &gt;&gt;&gt; temp_lst
  [OrderedDict([('Lastname', 'lastname.'), ('Name', 'abc')]), OrderedDict([('Lastname', 'lastname.'), ('Name', 'abc')]), OrderedDict([('Lastname', 'lastnamexyz.'), ('Name', 'xyz')])]
  </code></pre>
  
  <p>Both codes seems like the same then why i am getting <code>[None, None, None]</code> in first case and correct output in second case ?</p>