f.e., I have

```
declare class Foo extends Bar {
    foo: number
}

```

How do I declare that `foo` has a default value (or initial value) of, say, 60.

I tried

```
declare class Foo extends Bar {
    foo: number = 60
}

```

but I get an error like

```
4     foo: number = 60
                    ~~

path/to/something.js/Foo.d.ts/(4,28): error TS1039: Initializers are not allowed in ambient contexts.

```