Use static selection for identifier type

issue6374
review34781002

party.py

@@ -59,6 +59,7 @@ class PartyIdentifier:
     @classmethod
     def __setup__(cls):
         super(PartyIdentifier, cls).__setup__()
+        cls.type.selection.append(('sepa', 'SEPA Creditor Identifier'))
         cls._error_messages.update({
                 'unique_sepa': ('Party "%(party)s" has more than one '
                     'SEPA Creditor Identifier.'),
@@ -66,12 +67,6 @@ class PartyIdentifier:
                     '"%(party)s" is not valid.'),
                 })
 
-    @classmethod
-    def get_types(cls):
-        return super(PartyIdentifier, cls).get_types() + [
-            ('sepa', 'SEPA Creditor Identifier'),
-            ]
-
     def check_code(self):
         super(PartyIdentifier, self).check_code()
         if self.type == 'sepa':