title: What is a practical usage of Code Contracts in .NET 4.0?
body: <p>In order to fully understand and take advantage of the new features and enhancements provided with the coming of the new .NET Framework 4.0, I would like to get an example of <em>real-world</em> application of <a href="http://msdn.microsoft.com/en-us/library/system.diagnostics.contracts.aspx" rel="noreferrer">Code Contracts</a>.</p>
  
  <ol>
  <li><em>Anyone has a good example of application of this feature?</em></li>
  </ol>
  
  <p>I would like to get a code sample with a brief explanation to help me get up and running with it.</p>