1 files changed, 8 insertions, 1 deletions
diff --git a/src/Build/TopLevelHandler.php b/src/Build/TopLevelHandler.php
index 273b702..edb500d 100644
--- a/src/Build/TopLevelHandler.php
+++ b/src/Build/TopLevelHandler.php
@@ -9,19 +9,26 @@ use Symfony\Component\VarExporter\VarExporter;
 final class TopLevelHandler implements RegionHandler
 {
     /**
+     * A list of top-level region codes.
+     *
      * @var int[]
      */
     private array $data = [];
 
     public function handle(string $code, string $name): void
     {
-        if (substr($code, -4) !== '0000') {
+        if (! $this->isProvince($code)) {
             return;
         }
 
         $this->data[] = (int) $code;
     }
 
+    private function isProvince(string $code): bool
+    {
+        return substr($code, -4) === '0000';
+    }
+
     public function export(string $destination): void
     {
         $exported = VarExporter::export($this->data);