python: Fix __dict__ mutation abuse.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

corporate/tests/test_stripe.py

@@ -173,12 +173,11 @@ def generate_and_save_stripe_fixture(
                 stripe_object = mocked_function(*args, **kwargs)
         except stripe.error.StripeError as e:
             with open(fixture_path, "w") as f:
-                error_dict = e.__dict__
-                error_dict["headers"] = dict(error_dict["headers"])
+                error_dict = {**vars(e), "headers": dict(e.headers)}
                 f.write(
                     json.dumps(error_dict, indent=2, separators=(",", ": "), sort_keys=True) + "\n"
                 )
-            raise e
+            raise
         with open(fixture_path, "w") as f:
             if stripe_object is not None:
                 f.write(str(stripe_object) + "\n")

zerver/management/commands/list_realms.py

@@ -50,7 +50,7 @@ Usage examples:
         for realm in realms:
             # Start with just all the fields on the object, which is
             # hacky but doesn't require any work to maintain.
-            realm_dict = realm.__dict__
+            realm_dict = vars(realm).copy()
             # Remove a field that is confusingly useless
             del realm_dict["_state"]
             # Fix the one bitfield to display useful data