docs: @Override
      public void checkDocument(Document document) {
          document.getDefinitions().forEach(definition -> {
              if (!(definition instanceof OperationDefinition)
                  && !(definition instanceof FragmentDefinition)) {
  
                  String message = nonExecutableDefinitionMessage(definition);
                  addError(ValidationErrorType.NonExecutableDefinition, definition.getSourceLocation(), message);
              }
          });
      }