->arrayNode('paths')
    ->normalizeKeys(false)
    ->useAttributeAsKey('paths')
    ->beforeNormalization()
        ->always()
        ->then(function ($paths) {
            $normalized = [];
-            foreach ($paths as $path => $namespace) {
                if (\is_array($namespace)) {
                    // xml
                    $path = $namespace['value'];
                    $namespace = $namespace['namespace'];
                }