def ancestors(self, definition: Union[SLOT_OR_SLOTNAME,<EOL>CLASS_OR_CLASSNAME])-> List[Union[SlotDefinitionName, ClassDefinitionName]]:
definition = self.obj_for(definition)<EOL>if definition is not None:<EOL><INDENT>return [definition.name] + self.ancestors(definition.is_a)<EOL><DEDENT>else:<EOL><INDENT>return []<EOL><DEDENT>
Return an ordered list of ancestor names for the supplied slot or class

        @param definition: Slot or class name or definition
        @return: List of ancestor names