title: Test if a foreign key is None or not
body: <p>I have a model in django that points to another model. I want to test if it's set to something or not.</p>
  
  <pre><code>model.foreignkey = ForeignKeyField(...)
  </code></pre>
  
  <p>I want to test if this foreignkey is set or not - without actually fetching the foreign row's data (if the foreign key is set).</p>
  
  <pre><code>if model.foreignkey: # This line fetches data for 
      &lt;dosomething&gt;
  </code></pre>
  
  <p>Any help?</p>