function PairsObservable(o, scheduler) {
      this._o = o;
      this._keys = Object.keys(o);
      this._scheduler = scheduler;
      __super__.call(this);
    }
This method creates a new Observable instance with a variable number of arguments, regardless of number or type of the arguments.
@param {Scheduler} scheduler A scheduler to use for scheduling the arguments.
@returns {Observable} The observable sequence whose elements are pulled from the given arguments.