lib/plugins/aws/package/compile/layers/index.js/AwsCompileLayers/constructor
class AwsCompileLayers:  constructor(serverless, options) {
    this.serverless = serverless;
    this.options = options;
    const servicePath = this.serverless.config.servicePath || '';
    this.packagePath = this.serverless.service.package.path ||
      path.join(servicePath || '.', '.serverless');

    this.provider = this.serverless.getProvider('aws');

    this.hooks = {
      'package:compileLayers': () => BbPromise.bind(this)
        .then(this.compileLayers),
    };
  }