code: function dummyObsWrap(fn) {
      return function() {
          return Rx.Observable.create(function(observer) {
              fn(function(err, res) {
                  if(err) 
                      return observer.onError(err);
                  observer.onNext(res);
                  observer.onCompleted();
              });
          });
      }
  }
docs: Observable wrapper