update for subscription based fintech licensing

account_ebics/models/fintech_ebics_register.py

@@ -21,13 +21,16 @@ fintech_register_users = config.get('fintech_register_users')
 
 try:
     if fintech:
-        fintech_register_users = fintech_register_users \
+        fintech_register_users = (
+            fintech_register_users
             and [x.strip() for x in fintech_register_users.split(',')]
+            or None
+        )
         fintech.cryptolib = 'cryptography'
         fintech.register(
-            fintech_register_name,
-            fintech_register_keycode,
-            fintech_register_users)
+            name=fintech_register_name,
+            keycode=fintech_register_keycode,
+            users=fintech_register_users)
 except RuntimeError as e:
     if e.message == "'register' can be called only once":
         pass