[Zope3-Users] Weird error for a certain named attribute

[Maken Seteva]

Hello,
I have a very strange error that I cannot understand. I get an error  
for one of my attribute
only when it is named a certain name!  It seems like there is an old  
implementation of
it that is haunting in the background, how is this possible?

This cursed name is called "tags". This attribute is a list of  
TextLine. I get the error when I
don't add anything to the list in the adding view:

"TypeError: iteration over non-sequence"


However, if I rename the attribute to "wehoo" or really, anything  
else, I don't get the TypeError and
I can add my content object successfully (with an empty list for  
wehoo). Here's my component:

class IFoo(IContained):
	#...
      tags = List(
          title=_(u'Tags'),
          description=_(u'A list of keywords'),
          max_length=10,
          value_type=TextLine(title=_(u'Tag')),
          unique=True
          )
	#...


class Foo(Persistent):
	implements(IFoo)
	__name__ = __parent__ = None
	def __init__(self):
		#...
		self.tags = PersistentList()
		#...

No custom widgets used for this field...

I tried deleting all .pyc-files and deleting all old Foo objects, and  
the site i run for testing followed by
restarting the server. But adding new Foo objects still don't work.  
(But renaming tags to anything else
and then trying again will succeed).

Any ideas?

Regards Seteva