diff --git a/src/Rules/Nfe.php b/src/Rules/Nfe.php
index 65480c0..fde27f7 100644
--- a/src/Rules/Nfe.php
+++ b/src/Rules/Nfe.php
@@ -6,7 +6,7 @@
 use Illuminate\Contracts\Validation\Rule;
 
 
-class Nfe
+class Nfe implements Rule
 {
     public $allowMask;