code: function checkValidators(spec) {
    if (!spec.validate) return;
  
    let text;
    if (spec.validate.body) {
      text = 'validate.type must be declared when using validate.body';
      assert(/json|form/.test(spec.validate.type), text);
    }
  
    if (spec.validate.type) {
      text = 'validate.type must be either json, form, multipart or stream';
      assert(/json|form|multipart|stream/i.test(spec.validate.type), text);
    }
  
    if (spec.validate.output) {
      spec.validate._outputValidator = new OutputValidator(spec.validate.output);
    }
  
    // default HTTP status code for failures
    if (!spec.validate.failure) {
      spec.validate.failure = 400;
    }
  }
docs: Validate the spec.validators
  
  @param {Object} spec
  @api private