[FIX] dpd get label when no reference is sent

Author: florian-dacosta

roulier/carriers/dpd_fr_soap/encoder.py

@@ -25,9 +25,9 @@ def transform_input_to_carrier_webservice(self, data):
         )
         # dpd is configure with manage_multi_label = False, so always only 1 pack
         if (
-            data["parcels"]
-            and data["parcels"][0]["reference"]
-            and not data["service"]["reference2"]
+            data.get("parcels")
+            and data["parcels"][0].get("reference")
+            and not data["service"].get("reference2")
         ):
             data["service"]["reference2"] = data["parcels"][0]["reference"]