The puzzle `1303-7c7e06c0` from #1303 has to be resolved: https://github.com/php-coder/mystamps/blob/4c2104ad7a0860e73df660f3e32973e27cda6bd6/src/main/java/ru/mystamps/web/feature/series/SeriesServiceImpl.java#L143-L143 The puzzle was created by Slava Semushin on 28-Apr-20.