diff --git a/erpnext/hooks.py b/erpnext/hooks.py
index b301074..bf322b7 100644
--- a/erpnext/hooks.py
+++ b/erpnext/hooks.py
@@ -265,6 +265,8 @@
 }
 
 # On cancel event Payment Entry will be exempted and all linked submittable doctype will get cancelled.
+# to maintain data integrity we exempted payment entry. it will un-link when sales invoice get cancelled.
+# if payment entry not in auto cancel exempt doctype it will cancel payment entry.
 auto_cancel_exempt_doctypes = [
 	"Payment Entry"
 ]