Code review comment for lp:~frankban/juju-quickstart/env-manage-fields

The code LGTM with a few changes.

I am a bit confused as to where we're going with this work. It feels a
little like you're reinventing Zope. :) Let's not do that.

https://codereview.appspot.com/37820046/diff/1/quickstart/models/fields.py
File quickstart/models/fields.py (right):

https://codereview.appspot.com/37820046/diff/1/quickstart/models/fields.py#newcode63
quickstart/models/fields.py:63: - editable: True if the associated value
must be considered immutable.
This definition seems backwards. s/immutable/mutable/ ?

https://codereview.appspot.com/37820046/diff/1/quickstart/models/fields.py#newcode77
quickstart/models/fields.py:77: been previously validated.
Should there be a trap for that situation? A _validated flag?

https://codereview.appspot.com/37820046/