def update(self):
        """Called before the listing renders
        """
        super(BatchFolderContentsView, self).update()

        if self.on_batch_folder() and self.can_add_batches():
            self.context_actions[_("Add")] = {
                "url": "createObject?type_name=Batch",
                "permission": "Add portal content",
                "icon": "++resource++bika.lims.images/add.png"}
Called before the listing renders