lib/plugins/aws/package/compile/layers/index.js/AwsCompileLayers/compileLayers
class AwsCompileLayers:  compileLayers() {
    const allLayers = this.serverless.service.getAllLayers();
    return BbPromise.each(
      allLayers,
      layerName => this.compileLayer(layerName)
    );
  }