diff --git a/account_financial_report_webkit/report/aged_open_invoices.py b/account_financial_report_webkit/report/aged_open_invoices.py
index 85f6fd70..0241c85f 100644
--- a/account_financial_report_webkit/report/aged_open_invoices.py
+++ b/account_financial_report_webkit/report/aged_open_invoices.py
@@ -282,10 +282,12 @@ class AccountAgedOpenInvoicesWebkit(PartnersOpenInvoicesWebkit):
 
         :returns: delta in days
         """
-        sale_lines = [x for x in ledger_lines if x['jtype'] in REC_PAY_TYPE
-                      and line['rec_id'] == x['rec_id']]
-        refund_lines = [x for x in ledger_lines if x['jtype'] in REFUND_TYPE
-                        and line['rec_id'] == x['rec_id']]
+        sale_lines = [
+            x for x in ledger_lines if x['jtype'] in REC_PAY_TYPE and
+            line['rec_id'] == x['rec_id']]
+        refund_lines = [
+            x for x in ledger_lines if x['jtype'] in REFUND_TYPE and
+            line['rec_id'] == x['rec_id']]
         if len(sale_lines) == 1:
             reference_line = sale_lines[0]
         elif len(refund_lines) == 1: