Session throws fatal error, how to fix?

Question

PHP

After several refreshes of the page, it gives the following:
Fatal error: Class DatabaseSessionHandler contains 2 abstract methods and must therefore be declared abstract or implement the remaining methods (SessionHandlerInterface::open, SessionHandlerInterface::read) in DatabaseSessionHandler.php on line 4;
Before reboot everything works as it should. The session is written to the database.

Answer 1

It is written that the class does not fully implement the interface.
There are two missing functions in the DatabaseSessionHandler.
For whom the error messages came up with such detailed ones, no one reads anyway.