title: Django objects.filter() values_list() vs python list comprehension for __in query
body: <p>I have a quirk(?) with Django queryset filtering:</p>
  
  <pre><code>ipdb&gt; MagazineIssue.objects.filter(id__in=l_magazines.values_list('id'))
  Out[0]: []
  </code></pre>
  
  <p>or</p>
  
  <pre><code>ipdb&gt; MagazineIssue.objects.filter(id__in=[l_magazine.id for l_magazine in l_magazines])
  Out[0]: [&lt;MagazineIssue: Architecture Australia, Jan 1995 (#1)&gt;]
  </code></pre>
  
  <p>and</p>
  
  <pre><code>ipdb&gt; l_magazines.values_list('id')
  Out[0]: [(1,)]
  ipdb&gt; [l_magazine.id for l_magazine in l_magazines]
  Out[0]: [1]
  </code></pre>
  
  <p>so, how to use values_list()? (to produce):</p>
  
  <pre><code>[1]
  </code></pre>
  
  <p>or is python list comprehension the 'way to go'?</p>