docs: function _createResponseValidationError(messageFormat, res, subErrors) {
      var error = new VError(messageFormat, res.req.method, res.req.path, res.statusCode);
      error.name = 'ValidationError';
      error.subErrors = subErrors;
  
      var explainer = {
          message: error.message,
          status: 522,
          type: error.name
      };
      if (error.subErrors) {
          explainer.validation_errors = [];
          // eslint-disable-next-line lodash/prefer-map
          _.forEach(error.subErrors, function (subError) {
              explainer.validation_errors.push({
                  message: subError.message,
                  field: (subError.params.key) ? subError.dataPath + '/' + subError.params.key : subError.dataPath,
                  schemaPath: subError.schemaPath,
                  model: subError.model
              });
          });
      }
      return explainer;
  }