diff --git a/docs/patterns/fileuploads.rst b/docs/patterns/fileuploads.rst
index fef92c57..d3b16643 100644
--- a/docs/patterns/fileuploads.rst
+++ b/docs/patterns/fileuploads.rst
@@ -25,7 +25,7 @@ bootstrapping code for our application::
     from werkzeug.utils import secure_filename
 
     UPLOAD_FOLDER = '/path/to/the/uploads'
-    ALLOWED_EXTENSIONS = set(['txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif'])
+    ALLOWED_EXTENSIONS = {'txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif'}
 
     app = Flask(__name__)
     app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER