diff --git a/README.md b/README.md
index bde7baa..f080f0a 100644
--- a/README.md
+++ b/README.md
@@ -27,9 +27,8 @@ require_once __DIR__ . '/vendor/autoload.php';
 /**
  * Minimal options
  */
-$reflector = new \ReflectionClass(\PocztaPolska\EnumType\WsdlType::class);
 $options = [
-    WsdlToPhp\PackageBase\AbstractSoapClientBase::WSDL_URL => realpath(dirname($reflector->getFileName()) . '/' . \PocztaPolska\EnumType\WsdlType::WSDL_FILE);
+    WsdlToPhp\PackageBase\AbstractSoapClientBase::WSDL_URL => \PocztaPolska\EnumType\WsdlType::getPath(),
     WsdlToPhp\PackageBase\AbstractSoapClientBase::WSDL_CLASSMAP => \PocztaPolska\ClassMap::get(),
     WsdlToPhp\PackageBase\AbstractSoapClientBase::WSDL_LOGIN = "login",
     WsdlToPhp\PackageBase\AbstractSoapClientBase::WSDL_PASSWORD = "secret",
diff --git a/src/PocztaPolska/EnumType/WsdlType.php b/src/PocztaPolska/EnumType/WsdlType.php
index b73db2e..168a1ca 100644
--- a/src/PocztaPolska/EnumType/WsdlType.php
+++ b/src/PocztaPolska/EnumType/WsdlType.php
@@ -11,4 +11,13 @@ class WsdlType
 {
     public const WSDL_FILE = '../../../wsdl/en.wsdl';
     public const WSDL_TEST_FILE = '../../../wsdl/test/en.wsdl';
+
+    public static function getPath(bool $sandbox = false): string
+    {
+        if ($sandbox) {
+            return realpath(__DIR__ . '/' . self::WSDL_TEST_FILE);
+        }
+
+        return realpath(__DIR__ . '/' . self::WSDL_FILE);
+    }
 }