exception or returns ``None``. Used in deform as the
``validator=`` argument to a schema node, ensuring that the input
meets the requirements of the schema.
+ `TinyMCE <http://tinymce.moxiecode.com/index.php>`_ is a platform
+ released as Open Source under `LGPL
+ <http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html>`_ by
+ `Moxiecode Systems AB <http://www.moxiecode.com/>`_. It
+ has the ability to convert HTML TEXTAREA fields or other HTML
+ elements to editor instances. TinyMCE is very easy to integrate
+ into other Content Management Systems.