HarmonyOS ArkTS中如何实现泛型构造函数

interface BeeKeeper { 
  hasMask: boolean; 
} 
interface ZooKeeper { 
  nametag: string 
} 
interface Animal { 
  numLegs: number 
  keeper?: BeeKeeper | ZooKeeper 
} 
export class createInstance { 
  options: Animal 
 
  constructor(option: Animal) { 
    this.options = option; 
  } 
 
  getNumLegsValue(): number { 
    if(this.options.numLegs !== undefined ){ 
      return this.options.numLegs ; 
    } 
    return 0; 
  } 
 
  getKeeperValue(): BeeKeeper | ZooKeeper | undefined{ 
    if(this.options.keeper!== undefined){ 
      return this.options.keeper; 
    } 
    return undefined; 
  } 
} 
 
const numLegsValue = new createInstance({ numLegs: 123456 }).getNumLegsValue(); 
const KeeperValue = new createInstance({ numLegs: 123456, keeper: {hasMask: false} }).getKeeperValue();