title: deleting entries in a dictionary based on a condition
body: <p>I have a dictionary with names as key and (age, Date of Birth) tuple as the value for those keys. E.g.</p>
  
  <pre><code>dict = {'Adam' : (10, '2002-08-13'),
          'Eve'  : (40, '1972-08-13')}
  </code></pre>
  
  <p>I want to delete all the keys which have age > 30 for their age in value tuple, how can I do that? I am accessing age of each key using <code>dict[name][0]</code> where dict is my dictionary.</p>