[fix] [minor] validate warehouse user
diff --git a/stock/utils.py b/stock/utils.py
index 1f50164..983ee72 100644
--- a/stock/utils.py
+++ b/stock/utils.py
@@ -209,7 +209,7 @@
 	return wlist
 
 def validate_warehouse_user(warehouse):
-	if webnotes.session.user=="Administrator":
+	if webnotes.session.user=="Administrator" or not warehouse:
 		return
 	warehouse_users = [p[0] for p in webnotes.conn.sql("""select user from `tabWarehouse User`
 		where parent=%s""", warehouse)]