code: public com.google.cloud.datalabeling.v1beta1.PolylineOrBuilder getPolylineOrBuilder() {
      if (polyCase_ == 2) {
        return (com.google.cloud.datalabeling.v1beta1.Polyline) poly_;
      }
      return com.google.cloud.datalabeling.v1beta1.Polyline.getDefaultInstance();
    }
docs: <code>.google.cloud.datalabeling.v1beta1.Polyline polyline = 2;</code>