gistfile1.txt

class IMyEditComment(Interface):
      eff_date = schema.Datetime(title=_(u"Effective date"), required=False)
      exp_date = schema.Datetime(title=_(u"Expiration date"), required=False)
  
class MyEditCommentForm(EditCommentForm):
      """Form to edit an existing comment."""
      form.extends(EditCommentForm, ignoreButtons=True)
  
      fields += field.Fields(IMyEditComment)
  
      def updateWidgets(self):
          super(MyEditCommentForm, self).updateWidgets()
          val = getattr(self.context, 'eff_date', None)
          if val:
              self.widgets['eff_date'].value = val 
          val = getattr(self.context, 'exp_date', None)
          if val:
              self.widgets['exp_date'].value = val 
              
      @button.buttonAndHandler(_(u"edit_comment_form_button",
                               default=u"Edit comment"), name='comment')
      def handleComment(self, action):
  
          # Validate form
          data, errors = self.extractData()
          if errors:
              return

        self.context.eff_date = data['eff_date'].timetuple()
        self.context.exp_date = data['exp_date'].timetuple()