def METHOD_NAME(self, new_event):
    # event attachments
    for old_folder in self._query_folders(self.old_event.attachment_folders, True):
        self._clone_attachment_folder(old_folder, new_event)
    # session/contrib/subcontrib attachments
    if self._clone_nested_attachments:
        mapping = {LinkType.session: self._session_map,
                   LinkType.contribution: self._contrib_map,
                   LinkType.subcontribution: self._subcontrib_map}
        query = self._query_folders(self.old_event.all_attachment_folders, False)
        for old_folder in query:
            obj = old_folder.object
            if obj.is_deleted or (isinstance(obj, db.m.SubContribution) and obj.contribution.is_deleted):
                continue
            self._clone_attachment_folder(old_folder, mapping[old_folder.link_type][obj])