Remove arguments in super() calls.

They are no more needed in Python3 and usually result in unexpected
behavior when wrongly used (like e.g. the one introduced in
764cacc091 and solved meanwhile by
refactorization).

party.py

@@ -45,7 +45,7 @@ class Party(metaclass=PoolMeta):
         Args:
             records (list): records of party.party
         """
-        super(Party, cls).validate(records)
+        super().validate(records)
         for record in records:
             record.get_xrechnung_route_id()
 
@@ -57,7 +57,7 @@ class PartyConfiguration(metaclass=PoolMeta):
 
     @classmethod
     def __setup__(cls):
-        super(PartyConfiguration, cls).__setup__()
+        super().__setup__()
         cls.identifier_types.selection.append(
                 ('edoc_route_id', 'X-Rechnung Route-ID'))