docs: function _createRequestValidationError(message, parameterConfig, subErrors) {
      var error = new VError({
          name: 'ValidationError',
          constructorOpt: _createRequestValidationError
      }, message);
      error.source = { type: parameterConfig.in };
      if (/^(header|path|query|formData)$/.test(parameterConfig.in)) {
          error.source.name = parameterConfig.name;
      }
      error.subErrors = subErrors;
      _.forEach(error.subErrors, function (subError) {
          subError.source = subError.source || error.source;
          subError.field = _.get(subError, 'source.name',
              path.join((subError.dataPath || '/'), _.get(subError, 'params.key', '')));
          subError.in = _.get(subError, 'source.type');
  
      });
      return error;
  }