I am trying to create a service that returns an Observable that my components can subscribe to. But I get the following error:

```
Property 'subscribe' does not exist on type 'Observable'.

```

I am currently running build alpha.44, and below you will find some code that reproduces the problem.

```js
import {Http} from 'angular2/http';
import {Observable} from 'angular2/core';

export class Backend {
    http: Http;

    constructor(http: Http) {
        this.http = http;
        this.getTeams().subscribe();
    }

    public getTeams(): Observable {
        return this.http.get('/api/teams')
            .map(JSON.parse);
    }
}

```

Changing the code to return "any" type seems to work, but that removes some of the advantages of using TypeScript. Is there any good way to be able to use strict types for Observables in current builds of Angular2?