code: function(layers) {
              var lays = [];
              // if passing in no layers
              if (!layers) {
                  lays = [];
              }
              // if passing in an array of Layers
              // NOTE: layers could be an array or Kinetic.Collection.  for simplicity, I'm just inspecting
              // the length property to check for both cases
              else if (layers.length > 0) {
                  lays = layers;
              }
              // if passing in a Layer
              else {
                  lays = [layers];
              }
  
              this.layers = lays;
          }
docs: set layers to be redrawn on each animation frame
  @method
  @memberof Kinetic.Animation.prototype
  @param {Kinetic.Layer|Array} [layers] layer(s) to be redrawn.&nbsp; Can be a layer, an array of layers, or null.  Not specifying a node will result in no redraw.