title: use range with stepsize in yaml file
body: <p>In a .yaml file, I want to specify a range for a certain field, e.g., something like,
  <code>
  list_field: range(10,50,5)
  </code>
  In the above, I intend the <code>list_field</code> to be "pythonic" <code>range(10,50,5)</code>. Is there a way to achieve that?</p>