title: Executing code for a custom Django 404 page
body: <p>I am getting ready to deploy my first Django application and am hitting a bit of a roadblock.  My base template relies on me passing in the session object so that it can read out the currently logged in user's name.  This isn't a problem when I control the code that is calling a template.</p>
  
  <p>However, as part of getting this app ready to be deployed, I need to create a 404.html page.  I extended my base template just like I've done with my other pages, but I don't see a way to pass in the session object so that I can utilize it.  Is there a way to have Django call a custom method to render your 404 rather than just rendering your 404.html for you?</p>