title: Calculating all IPs in subnet using Python 2.7 built in modules only
body: <p>I am wondering how to create a script that takes a cidr notation like this:</p>
  
  <pre><code>204.15.20.0/22
  </code></pre>
  
  <p>And calculates all possible IP addresses in that range.</p>
  
  <pre><code>204.15.20.0
  ...
  ...
  204.15.23.255
  </code></pre>
  
  <p>Now I finally know the math behind this, I was wondering how I could make such a module in python.</p>
  
  <p>I am aware of ready-available modules such as netaddr.IPNetwork() but I am wondering how I would do this, using only the built-in modules in Python 2.7</p>
  
  <p>Thanks :)</p>