How to override a method from an abstract TypeScript class?

Question

typescript

The abstract class has a method:

public prop<K extends keyof RootObject>(key: K) {
    return this._has(key) ? this.data[key] : null;
 }

I tried to override it in the descendant classes:

public prop<K extends keyof IParentProfile>(key: K) {
    return this._has(key) ? this.model[key] : null;
  }

But it doesn't work, IDE writes incompatible override