diff --git a/tests/test_simple_remote.py b/tests/test_simple_remote.py
index 2b581ac9..9d12e618 100755
--- a/tests/test_simple_remote.py
+++ b/tests/test_simple_remote.py
@@ -1067,6 +1067,7 @@ def test_child_process_dies(self):
             # try to handle children list -- missing processes will have ptype "ProcessType.Unknown"
             [ProcessProxy(p) for p in children]
 
+    @staticmethod
     def helper__restore_envvar(name, prev_value):
         if prev_value is None:
             os.environ.pop(name, None)