Skeleton is ready

app/Kernel/DateTime/Format.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Kernel\DateTime;
+
+enum Format: string
+{
+    case CutISO8601DateTime = 'Y-m-d H:i:s';
+    case CutISO8601Date = 'Y-m-d';
+}

app/Kernel/DateTime/Util.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Kernel\DateTime;
+
+use DateTimeInterface;
+
+class Util
+{
+    public static function toString(
+        DateTimeInterface $datetime,
+        Format $format
+    ): string{
+        return $datetime->format($format->value);
+    }
+}