Logging to files

Good day!
I try to use file_logger lib. I need to write messages of level 1 (LL_WARN). By default “file_logger.level” is 2, in mos.yml file I added string - [“file_logger.level”, 1]. I added some test LL_WARN messages in code and want to read created log file, but the file is empty.
What’s wrong?

Upd: If I change level to 2, I see messages of levels 0,1 and 2 (LL_ERROR, LL_WARN, LL_INFO).