From 74a121da74af8928cb212e550869fc4c7d511cde Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@pythonspeed.com>
Date: Tue, 6 Jun 2023 11:47:36 -0400
Subject: [PATCH] Fix bug which meant object could not be created.

---
 src/allmydata/storage/http_client.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/allmydata/storage/http_client.py b/src/allmydata/storage/http_client.py
index fe2545c03..8cf79843f 100644
--- a/src/allmydata/storage/http_client.py
+++ b/src/allmydata/storage/http_client.py
@@ -330,9 +330,9 @@ class StorageClientFactory:
 
     # If set, we're doing unit testing and we should call this with any
     # HTTPConnectionPool that gets passed/created to ``create_agent()``.
-    TEST_MODE_REGISTER_HTTP_POOL = ClassVar[
+    TEST_MODE_REGISTER_HTTP_POOL: ClassVar[
         Optional[Callable[[HTTPConnectionPool], None]]
-    ]
+    ] = None
 
     @classmethod
     def start_test_mode(cls, callback: Callable[[HTTPConnectionPool], None]) -> None: