title: Python lazy list
body: <p>I would like create my own collection that has all the attributes of python list and also knows how to save/load itself into/from a database.  Also I want to make the load implicit and lazy, as in it doesn't happen at the point of creation of the list, but waits until its first used.</p>
  
  <p>Is there a single<code>__xxx__</code>method I can override to load the list on first usage of any list property  (such as<code>len</code>,<code>getitem</code>,<code>iter</code>...etc) without having to override them all?</p>