diff --git a/ihatemoney/models.py b/ihatemoney/models.py
index a7a7b170..63efdbed 100644
--- a/ihatemoney/models.py
+++ b/ihatemoney/models.py
@@ -256,6 +256,12 @@ class Project(db.Model):
         )
 
     def get_bill_weights(self):
+        """
+        Return all bills for this project, along with the sum of weight for each bill.
+        Each line is a (float, Bill) tuple.
+
+        Result is unordered.
+        """
         return (
             db.session.query(func.sum(Person.weight), Bill)
             .options(orm.subqueryload(Bill.owers))
@@ -267,6 +273,7 @@ class Project(db.Model):
         )
 
     def get_bill_weights_ordered(self):
+        """Ordered version of get_bill_weights"""
         return self.ordered_bills(self.get_bill_weights())
 
     def get_member_bills(self, member_id):
diff --git a/ihatemoney/web.py b/ihatemoney/web.py
index 83e2c98e..b843f605 100644
--- a/ihatemoney/web.py
+++ b/ihatemoney/web.py
@@ -653,11 +653,13 @@ def list_bills():
     # set the last selected payer as default choice if exists
     if "last_selected_payer" in session:
         bill_form.payer.data = session["last_selected_payer"]
-    bills = g.project.get_bill_weights_ordered().paginate(per_page=100, error_out=True)
+
+    # Each item will be (weight_sum, Bill) tuple
+    weights_bills = g.project.get_bill_weights_ordered().paginate(per_page=100, error_out=True)
 
     return render_template(
         "list_bills.html",
-        bills=bills,
+        bills=weights_bills,
         member_form=MemberForm(g.project),
         bill_form=bill_form,
         csrf_form=csrf_form,