title: print values from json and ignore keys
body: <p>I'm getting a server list from <code>aws</code> and print them, however sometimes I get some missing keys:</p>
  <pre><code>&gt;&gt;&gt; servers=ec2_client.describe_instances()
  &gt;&gt;&gt; for r in servers['Reservations']:
  ...     for i in r['Instances']:
  ...         print(i['InstanceId'], i['PrivateIpAddress'], i['PublicIpAddress'])
  ...
  i-x x.y.z.p x.y.z.w
  i-y x.y.z.p x.y.z.w
  i-t x.y.z.p x.y.z.w
  i-r x.y.z.p x.y.z.w
  i-e x.y.z.p x.y.z.w
  i-s x.y.z.p x.y.z.w
  i-e x.y.z.p x.y.z.w
  i-r x.y.z.p x.y.z.w
  Traceback (most recent call last):
    File &quot;&lt;stdin&gt;&quot;, line 3, in &lt;module&gt;
  KeyError: 'PublicIpAddress'
  </code></pre>
  <p>How do I print it while ignoring missing keys (in a nice way)?</p>