diff --git a/README.md b/README.md
index 87db7eb3..2c3644ff 100644
--- a/README.md
+++ b/README.md
@@ -219,7 +219,8 @@ class ApplicationController < ActionController::Base
   protected
 
   def devise_parameter_sanitizer
-    if resource_class.is_a?(User)
+    case resource_class
+    when User
       User::ParameterSanitizer.new(User, :user, params)
     else
       super # Use the default one