diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index 86b7aaa..e83873f 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -9,7 +9,6 @@
 from frappe.model.utils import get_fetch_values
 from frappe.utils import (
 	add_days,
-	add_months,
 	cint,
 	cstr,
 	flt,