anchor.diff:      return c.future;
     }
   
  -  /**
  -   * Changes the password of an existing user using an email / password combination.
  -   */
     Future changePassword(Map credentials) {
       var c = new Completer();
       _fb.callMethod('changePassword', [
  
positive.code:     return c.future;
    }
  
    /**
     * Push generates a new child location using a unique name and returns a
     * Firebase reference to it. This is useful when the children of a Firebase
     * location represent a list of items.
     *
     * The unique name generated by push() is prefixed with a client-generated
     * timestamp so that the resulting list will be chronologically sorted.
     */
    Firebase push({value, onComplete}) =>
        new JsFirebase.fromJsObject(_fb.callMethod('push', [
          value == null ? null : jsify(value),
  
negative.code:     return c.future;
    }
  
    Future authWithOAuthRedirect(provider, {remember: 'default', scope: ''}) {
      var c = new Completer();
      _fb.callMethod('authWithOAuthRedirect', [
  