title: Using 'in' to match an attribute of Python objects in an array
body: <p>I don't remember whether I was dreaming or not but I seem to recall there being a function which allowed something like,</p>
  
  <pre><code>foo in iter_attr(array of python objects, attribute name)</code></pre>
  
  <p>I've looked over the docs but this kind of thing doesn't fall under any obvious listed headers</p>