diff --git a/erpnext/controllers/sales_and_purchase_return.py b/erpnext/controllers/sales_and_purchase_return.py
index 5412807..0074560 100644
--- a/erpnext/controllers/sales_and_purchase_return.py
+++ b/erpnext/controllers/sales_and_purchase_return.py
@@ -71,7 +71,7 @@
 	already_returned_items = get_already_returned_items(doc)
 
 	# ( not mandatory when it is Purchase Invoice or a Sales Invoice without Update Stock )
-	warehouse_mandatory = not ((doc.doctype=="Purchase Invoice" or doc.doctype=="Sales Invoice") and not doc.update_stock))
+	warehouse_mandatory = not ((doc.doctype=="Purchase Invoice" or doc.doctype=="Sales Invoice") and not doc.update_stock)
 
 	items_returned = False
 	for d in doc.get("items"):