parser lieferservice: support delivery costs

scripts/order-confirmation-mail-parser

@@ -451,11 +451,17 @@ def parse_lieferservice(msg):
                 ))
 
     delivery_costs = order_match_groups['delivery_costs'].strip()
-    assert delivery_costs in ['FREE', 'GRATIS']
-    order.items.append(dingguo.Item(
-        name = u'Delivery',
-        price_brutto = dingguo.Sum(float('0'.replace(',', '.')), u'EUR'),
-        ))
+    if delivery_costs in ['FREE', 'GRATIS']:
+        order.items.append(dingguo.Item(
+            name = u'Delivery',
+            price_brutto = dingguo.Sum(0.0, u'EUR'),
+            ))
+    else:
+        unit, value = delivery_costs.split(' ')
+        order.items.append(dingguo.Item(
+            name = u'Delivery',
+            price_brutto = dingguo.Sum(float(value.replace(',', '.')), unit),
+            ))
 
     return [order]