How to convert unicode to koi8-r?

[AlekseyPython]

I don't see a reason why you should mess with this at all.
Try avoid encoding/decoding at all,let DB handle if needed.
If example test sqlite3 with Python 3.7.
There is no need to do anything,Python 3 text(Unicode default) will go in out DB without any problems.

Thanks you for the answer.
In your case the text will actually be placed in the database, but it will take up twice the amount of disk space. Therefore, reading and writing data from database will be twice as slow. I can set a more economical charset in MariaDB to avoid unnecessary costs. I want to prepare data in Python (excluding only unsupported koi8-r characters), so that they are written to the database as completely as possible.