diff --git a/src/allmydata/test/cli/wormholetesting.py b/src/allmydata/test/cli/wormholetesting.py
index d4e53a342..be94a7981 100644
--- a/src/allmydata/test/cli/wormholetesting.py
+++ b/src/allmydata/test/cli/wormholetesting.py
@@ -76,7 +76,7 @@ class MemoryWormholeServer(object):
         stderr: TextIO=stderr,
         _eventual_queue: Optional[Any]=None,
         _enable_dilate: bool=False,
-    )-> _MemoryWormhole:
+    ) -> _MemoryWormhole:
         """
         Create a wormhole.  It will be able to connect to other wormholes created
         by this instance (and constrained by the normal appid/relay_url