docs: @Override
      public void validate(ValidationHelper helper, Context context, String key, Operation t) {
          if (t != null) {
              final String id = t.getOperationId();
              if (id != null && helper.addOperationId(id)) {
                  final String message = Tr.formatMessage(tc, "operationIdsMustBeUnique", id);
                  helper.addValidationEvent(new ValidationEvent(Severity.ERROR, context.getLocation("operationId"), message));
              }
              final APIResponses responses = t.getResponses();
              ValidatorUtils.validateRequiredField(responses, context, "responses").ifPresent(helper::addValidationEvent);
          }
      }