Automated change: Fix sanity tests

src/python/grpcio/grpc/aio/_channel.py

diff --git a/src/python/grpcio/grpc/aio/_channel.py b/src/python/grpcio/grpc/aio/_channel.py
index 30fef12..5da97d9 100644
--- a/src/python/grpcio/grpc/aio/_channel.py
+++ b/src/python/grpcio/grpc/aio/_channel.py
@@ -407,7 +407,9 @@
     async def __aexit__(self, exc_type, exc_val, exc_tb) -> None:
         await self._close(None)
 
-    async def _close(self, grace: Optional[float]) -> None:  # pylint: disable=too-many-branches
+    async def _close(
+        self, grace: Optional[float]
+    ) -> None:  # pylint: disable=too-many-branches
         if self._channel.closed():
             return