title: Django + Factory Boy: Use Trait to create other factory objects
body: <p>Is it possible to use Traits (or anything else in Factory Boy) to trigger the creation of other factory objects? For example: In a User-Purchase-Product situation, I want to create a user and inform that this user has a product purchased with something simple like that:</p>
  
  <pre><code>UserFactory.create(with_purchased_product=True)
  </code></pre>
  
  <p>Because it feels like too much trouble to call <strong>UserFactory</strong>, <strong>ProductFactory</strong> and <strong>PurchaseFactory</strong>, then crate the relationship between them. There has to be a simpler way to do that.</p>
  
  <p>Any help would be appreciated.</p>