title: Django templates: testing if variable is in list or dict
body: <p>was wondering if there is a way to test if a variable is inside of a list or dict in django using the built in tags and filters.</p>
  
  <p>Ie: <code>{% if var|in:the_list %}</code></p>
  
  <p>I don't see it in the docs, and will attempt something custom if not, but I don't want to do something that has already been done.</p>
  
  <p>Thanks</p>