PYRE_MISSING_ANNOTATIONS in subprocess_test.py (#1606)

Summary: Pull Request resolved: #1606

Reviewed By: frbng

Differential Revision: D114078811

Author: Code Quality Bot

tests/pipeline/subprocess_test.py

@@ -433,7 +433,7 @@ def _src6() -> Iterable[int]:
     return SleepSourceIterable(3)
 
 
-def _fail_initializer():
+def _fail_initializer() -> None:
     raise RuntimeError("Failed!")