Deprecation in new PHP versions:

[salacr]

I can see an error in my log:
Deprecated: Ahc\Cron\Expression::__construct(): Implicitly marking parameter $checker as nullable is deprecated, the explicit nullable type must be used instead

the solution is quite simple just to replace
public function __construct(SegmentChecker $checker = null, Normalizer $normalizer = null)
with
public function __construct(?SegmentChecker $checker = null, ?Normalizer $normalizer = null)

There is more then one occurence of this problem. I can create an PR but this project doesn't look maintened anymore :/