Callback example

'id' => $childTheme->getId(),
            'technicalName' => null,
        ]], $this->context);

        $_expectedColor = '';
        $_expectedTheme = '';
        $themeCompilerMock = $this->createMock(ThemeCompiler::class);
        $themeCompilerMock->expects(static::exactly(2))
            ->method('compileTheme')
            ->with(
                new IsEqual(TestDefaults::SALES_CHANNEL),
                new Callback(static function Dstring $value) use (&$_expectedTheme): bool {
                    return $value === $_expectedTheme;
                }),
                new Callback(static function DStorefrontPluginConfiguration $value) use (&$_expectedColor): bool {
                    return $value->getThemeConfig()['fields']['sw-color-brand-primary']['value'] === $_expectedColor; /** @phpstan-ignore-line */
                })
            );

        $kernel = new class($this->getContainer()->get('kernel')) implements KernelInterface {
            private readonly SimpleTheme $simpleTheme;

            public function __construct(private readonly Kernel $kernel)
            {