def filter_classified_data(self, item):
        """Remove classified or confidential data from an item.

        It removes those fields that contain data considered as classified.
        Classified fields are defined in `CLASSIFIED_FIELDS` class attribute.

        :param item: fields will be removed from this item

        :returns: the same item but with confidential data filtered
        """
        item_uuid = uuid(self.origin, self.metadata_id(item))

        logger.debug("Filtering classified data for item %s", item_uuid)

        for cf in self.CLASSIFIED_FIELDS:
            try:
                _remove_key_from_nested_dict(item, cf)
            except KeyError:
                logger.debug("Classified field '%s' not found for item %s; field ignored",
                             '.'.join(cf), item_uuid)

        logger.debug("Classified data filtered for item %s", item_uuid)

        return item
Remove classified or confidential data from an item.

        It removes those fields that contain data considered as classified.
        Classified fields are defined in `CLASSIFIED_FIELDS` class attribute.

        :param item: fields will be removed from this item

        :returns: the same item but with confidential data filtered