lib/plugins/package/index.js/Package/constructor
class Package:  constructor(serverless, options) {
    this.serverless = serverless;
    this.options = options;

    Object.assign(
      this,
      validate,
      zipService,
      packageService,
      cleanup
    );

    this.hooks = {
      'deploy:cleanup': () => BbPromise.bind(this)
        .then(this.cleanup),

      'deploy:createDeploymentArtifacts': () => BbPromise.bind(this)
        .then(this.validate)
        .then(this.packageService),
    };
  }