The Domain layer should contain business logic, domain models (aggregates with events, entities e.t.c.), and what is [this](https://github.com/CodelyTV/php-ddd-example/blob/main/src/Shared/Domain/Utils.php)?
The Domain layer should contain business logic, domain models (aggregates with events, entities e.t.c.), and what is this?