Housekeeping.

[wolnelektury.git] / src / catalogue / models / book.py

diff --git a/src/catalogue/models/book.py b/src/catalogue/models/book.py
index 01f0281..9e0f7c8 100644 (file)
--- a/src/catalogue/models/book.py
+++ b/src/catalogue/models/book.py
@@ -738,6 +738,8 @@ class Book(models.Model):
     def update_references(self):
         from references.models import Entity, Reference
         master = self.get_master()
+        if master is None:
+            master = []
         found = set()
         for i, sec in enumerate(master):
             for ref in sec.findall('.//ref'):