question: protected Set < String > allowedDuplicateErrorCodes ( ) { return Collections . emptySet ( ) ; }
target:  Override this if the should_not_contain_same_error_codes_for_different_instances_that_are_not_wrappers test is failing and you *really* want to allow one or more of your error codes to have duplicate ApiErrors that are not wrappers. This should be used with care.