From 4231054f390cf855d78d220030b543781b6e8044 Mon Sep 17 00:00:00 2001
From: Bernat Brunet Torruella <bernat@nan-tic.com>
Date: Thu, 3 Jan 2019 15:58:16 +0100
Subject: [PATCH] Fix bug when add SII keys to invoice automatically based on
 tax definition

---
 invoice.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/invoice.py b/invoice.py
index a39099c..3886f34 100644
--- a/invoice.py
+++ b/invoice.py
@@ -169,7 +169,7 @@ class Invoice(metaclass=PoolMeta):
     def _set_sii_keys(self):
         tax = None
         for t in self.taxes:
-            if t.tax.tax_used:
+            if t.tax.sii_book_key:
                 tax = t.tax
                 break
         if not tax: