diff --git a/Internal/Exporter.php b/Internal/Exporter.php
index d1ee987..7626a0a 100644
--- a/Internal/Exporter.php
+++ b/Internal/Exporter.php
@@ -78,7 +78,7 @@ public static function prepare($values, $objectsPool, &$refsPool, &$objectsCount
 
             if ($reflector->hasMethod('__serialize')) {
                 if (!$reflector->getMethod('__serialize')->isPublic()) {
-                    throw new \Error(sprintf('Call to %s method %s::__serialize()', $reflector->getMethod('__serialize')->isProtected() ? 'protected' : 'private', $class));
+                    throw new \Error(sprintf('Call to %s method %s::__serialize().', $reflector->getMethod('__serialize')->isProtected() ? 'protected' : 'private', $class));
                 }
 
                 if (!\is_array($properties = $value->__serialize())) {