ArkTS要如何使用this，有人知道吗？

class A {
  count: string = 'a';
  m(i: string): void {
    this.count = i;
  }
}

function main(): void {
  let a = new A();
打印a
  a.m('b');
打印b
}

class Test1 {
  value: string = '';
  constructor (value: string) {
    this.value = value;
  }
  foo() {
    console.log(this.value);
  }
}

let obj: Test1 = new Test1('abc');
obj.foo();