code: function (tilePoint) {
      var EMPTY_GIF = "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7";
      this._adjustTilePoint(tilePoint);
  
      var tiles = [EMPTY_GIF];
      if(this.tilejson) {
        tiles = this.tilejson.tiles;
      }
  
      var index = (tilePoint.x + tilePoint.y) % tiles.length;
  
      return L.Util.template(tiles[index], L.Util.extend({
        z: this._getZoomForUrl(),
        x: tilePoint.x,
        y: tilePoint.y
      }, this.options));
    }
docs: overwrite getTileUrl in order to support different tiles subdomains in tilejson way