diff --git a/tests/test_vendor_sap.py b/tests/test_vendor_sap.py
index 6e1eb4b..ec1acef 100644
--- a/tests/test_vendor_sap.py
+++ b/tests/test_vendor_sap.py
@@ -275,7 +275,7 @@ def test_add_btp_token_to_session_invalid_clientid():
 
 class MockHeaderResponse(NamedTuple):
     headers: dict
-    content: ByteString = b''
+    content: bytes = b''
     status_code: int = 200