How to use the @aurelia/validation.ValidationRules function in @aurelia/validation

//   .withMessage('hdhkjdah')
    //   .matches(/www/)
    //   .withMessageKey('re')

    //   .ensure("items[0].prop")
    //   .required()
    //   .withMessage('hdhkjdah')
    //   .matches(/www/)
    //   .withMessageKey('re')

    //   .rules
    //   ;

    // console.log(rules);

    const rules1 = new ValidationRules()
      .ensure("b.c")
      .required()
      .ensure("d")
      .required()
      .on(this.a)
      .rules;
    const result = await this.validator.validateObject(this.a, rules1);
    console.log(result);
  }