diff --git a/role.go b/role.go
index 448ae1c..e5034aa 100644
--- a/role.go
+++ b/role.go
@@ -29,8 +29,7 @@ func (role *Role) Register(name string, fc Checker) {
 		role.definitions = map[string]Checker{}
 	}
 
-	definition := role.definitions[name]
-	if definition != nil {
+	if _, ok := role.definitions[name]; ok {
 		fmt.Printf("Role `%v` already defined, overwrited it!\n", name)
 	}
 	role.definitions[name] = fc