title: Django ORM - Dynamically add When to Case
body: <p>I have a list of lists</p>
  
  <pre><code>my_list= [
      [1,2,3],
      [4,5,6],
      ...
  ]
  </code></pre>
  
  <p>I'd like to annotate some values like this:</p>
  
  <pre><code>from django.db.models import CharField, Case, When, Value
  
  MyModel.objects.filter(...).annotate(label=Case(When(some_value__in=my_list[0] then=Value('first list')), output_field=CharField()))
  </code></pre>
  
  <p>Now I need add a similar <code>When</code> for the other lists in <code>my_list</code>, but my_list could have different lengths.</p>
  
  <p>How could I do this?</p>