class ProtobufUtil {

    static Timestamp timestampFromMillis(long timestampMillis) {<FILL_FUNCTION_BODY>}
}

        return Timestamp.newBuilder()
                .setSeconds(timestampMillis / 1000L)
                .setNanos((int) (timestampMillis % 1000L * 1000000L))
                .build();
    
<no_super_class>