title: Django-filter: filtering by model property
body: <p>I read on <a href="https://stackoverflow.com/questions/1205375/filter-by-property">several</a> <a href="https://github.com/carltongibson/django-filter/issues/889" rel="nofollow noreferrer">places</a> that it is not possible to filter Django querysets using properties because Django ORM would have no idea how to convert those into SQL.</p>
  
  <p>However, once the data are fetched and loaded into memory, it <em>shall</em> be possible to filter them in Python using those properties.</p>
  
  <p>And my question: is there any library that allows the querysets to be filtered by properties in memory? And if not, how exactly must the querysets be tampered with so that this becomes possible? And how to include <code>django-filter</code> into this?</p>