diff --git a/payments/core.py b/payments/core.py
index 922001605..8b8ff0c97 100644
--- a/payments/core.py
+++ b/payments/core.py
@@ -155,14 +155,14 @@ def autocomplete_with_subscription(self, payment):
         Throws RedirectNeeded if there is problem with the payment
         that needs to be solved by user.
         """
-        raise NotImplementedError()
+        raise NotImplementedError
 
     def cancel_subscription(self, subscription):
         """
         Cancel subscription
         Used by providers, that use provider initiated cancellation workflow
         """
-        raise NotImplementedError()
+        raise NotImplementedError
 
     def capture(self, payment, amount=None):
         raise NotImplementedError
diff --git a/payments/models.py b/payments/models.py
index ba07160bd..fdc6174c4 100644
--- a/payments/models.py
+++ b/payments/models.py
@@ -1,10 +1,9 @@
 from __future__ import annotations
 
-import json
 import enum
+import json
 from typing import Iterable
 from typing import Optional
-from typing import Union
 from uuid import uuid4
 
 from django.db import models
@@ -73,10 +72,10 @@ def set_recurrence(self, token: str, **kwargs):
         self.token = token
 
     def get_period(self) -> int:
-        raise NotImplementedError()
+        raise NotImplementedError
 
     def get_unit(self) -> TimeUnit:
-        raise NotImplementedError()
+        raise NotImplementedError
 
     def cancel(self):
         """
@@ -244,7 +243,7 @@ def get_payment_url(self) -> str:
         Get the url the view that handles the payment (payment_details() in documentation)
         For now used only by PayU provider to redirect users back to CVV2 form
         """
-        raise NotImplementedError()
+        raise NotImplementedError
 
     def get_subscription(self) -> Optional[BaseSubscription]:
         """