ADD sealed examples

Author: DaveLiddament

examples/sealed/sealedClasses.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SealedClasses;
+
+use DaveLiddament\PhpLanguageExtensions\Sealed;
+
+class Success extends Response // OK
+{
+}
+
+class Failed extends Response // OK
+{
+}
+
+#[Sealed(Success::class, Failed::class)]
+class Response
+{
+}
+
+
+class AnotherClass extends Response // ERROR AnotherClass can not extend Response
+{
+}

examples/sealed/sealedInterfaces.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SealedInterfaces;
+
+use DaveLiddament\PhpLanguageExtensions\Sealed;
+
+class Success implements Response // OK
+{
+}
+
+class Failed implements Response // OK
+{
+}
+
+#[Sealed(Success::class, Failed::class)]
+interface Response
+{
+}
+
+
+class AnotherClass implements Response // ERROR AnotherClass can not implement Response
+{
+}