(I have read [this post](https://stackoverflow.com/questions/39231151/how-to-use-bluebird-with-current-typescript) but it is from August and it does not answer my question for the current typescript version.)

I'm currently using Typescript 1.8 in my project and this works fine:

```
import * as Promise from "bluebird";
async function f() : Promise<void> {
  return Promise.delay(200);
}

```

But if I try to compile with Typescript 2.1:

```
index.ts(2,16): error TS1059: Return expression in async function does not have a valid callable 'then' member.

```

Googling the issue of using Bluebird Promises in Typscript, I have also found many github discussions, comments and PRs, but they are all very hard to grasp and while discussing interesting points, I can't find anywhere that says how I'm supposed to get this to work now.

So, how am I supposed to be able to use Bluebird for Promises in Typescript 2.1?