code: function (tips, channel) {
          if (!this.api_key) throw new ChangeTipException(300);
  
          var deferred = Q.defer(),
              params;
  
          params = {
              tips: tips instanceof Array ? tips.join(",") : tips,
              channel: channel || ''
          };
  
          this._send_request({}, 'tips', params, Methods.GET, deferred);
          return deferred.promise;
      }
docs: Retrieve tips from the ChangeTip API
  @param {string|string[]} tips Single or collection of tip identifiers to retrieve
  @param {string} [channel] Channel to filter results. (github, twitter, slack, etc)
  @returns {promise.promise|jQuery.promise|promise|Q.promise|jQuery.ready.promise|l.promise}