I noticed that PersistentList and PersistentDict do not satisfy zope.schema.List or zope.schema.Dict, which is rather annoying. For example: class IBlogPost(Interface): tags = zope.schema.List(title=u'Tags', value_type=zope.schema.TextLine) class BlogPost(Persistent): implements(IBlogPost) tags = FieldProperty(IBlogPost['tags']) def __init__(self): super(BlogPost, self).__init__() self.tags = persistent.list.PersistentList() #aaah, WrongType error... will throw a WrongType: ([], <type 'list'>) error, which is especially confusing because the repr for PersistentList makes it look an awful lot like a regular list. same thing happens with PersistentDict. I would like to modify zope.schema._bootstrapfields by changing the _type attribute of the List class to (list, UserList), and do the same for Dict with (dict, UserDict). Then anything inheriting from UserList (including PersistentList) will satisfy the schema. Can anyone think of a reason why this would be bad? -- Paul Carduner http://www.carduner.net