code: function createLayers() {
    if (!this.serverless.service.layers) {
      this.serverless.service.layers = {};
    }
    this.serverless.service.layers['pythonRequirements'] = Object.assign(
      {
        artifact: path.join('.serverless', 'pythonRequirements.zip'),
        name: `${
          this.serverless.service.service
        }-${this.serverless.providers.aws.getStage()}-python-requirements`,
        description:
          'Python requirements generated by serverless-python-requirements.',
        compatibleRuntimes: [this.serverless.service.provider.runtime]
      },
      this.options.layer
    );
  
    return BbPromise.resolve();
  }
docs: Creates a layer on the serverless service for the requirements zip.
  @return {Promise} empty promise