Searching 2 dimensional dictionary
<p>I have a 2 dimensinal dictionary representing people.  Here's an example of it:</p>

<pre><code>&gt;&gt;&gt; people = {'pk1':{'firstname':'Brian', 'age':42}, 'pk2':{'firstname':'Alex',
'age':50}}
</code></pre>

<p>As can be seen, there is a primary key in each entry. Each one then points to a dictionary containing information about a specific person.  How do I search the overall 'people' dictionary to return me all people who have the age 42? </p>
