title: SqlAlchemy : delete, update through an association proxy
body: <p>I would like to know what is the best way to use an association proxy for the update and delete operation :</p>
  
  <p>I have a class <code>Person</code>  which can have some <code>tickets</code> as association
  so I do <code>Person.tickets.append(ticket1)</code></p>
  
  <p>now can I do as well <code>Person.tickets.remove(ticket1)</code> ? Or <code>Person.tickets.clear()</code> ?
  I tried both and it works, however I'm not sure it is the proper way...</p>