def desc_for(self, obj: Element, doing_descs: bool) -> str:
        """ Return a description for object if it is unique (different than its parent)

        @param obj: object to be described
        @param doing_descs: If false, always return an empty string
        @return: text or empty string
        """
        if obj.description and doing_descs:
            if isinstance(obj, SlotDefinition) and obj.is_a:
                parent = self.schema.slots[obj.is_a]
            elif isinstance(obj, ClassDefinition) and obj.is_a:
                parent = self.schema.classes[obj.is_a]
            else:
                parent = None
            return '' if parent and obj.description == parent.description else obj.description
        return ''
Return a description for object if it is unique (different than its parent)

        @param obj: object to be described
        @param doing_descs: If false, always return an empty string
        @return: text or empty string