diff --git a/src/aiida/engine/daemon/worker.py b/src/aiida/engine/daemon/worker.py
index ec759fce4..7455c4dcc 100644
--- a/src/aiida/engine/daemon/worker.py
+++ b/src/aiida/engine/daemon/worker.py
@@ -12,7 +12,6 @@
 import logging
 import signal
 import sys
-import threading
 
 from aiida.common.log import configure_logging
 from aiida.engine.daemon.client import get_daemon_client
@@ -38,6 +37,7 @@ async def shutdown_worker(runner: Runner) -> None:
 
     LOGGER.info('Daemon worker stopped')
 
+
 def create_daemon_runner(manager: Manager) -> 'Runner':
     """Create and return a new daemon runner.
 
@@ -70,6 +70,7 @@ def create_daemon_runner(manager: Manager) -> 'Runner':
 
     return runner
 
+
 def start_daemon_worker(foreground: bool = False) -> None:
     """Start a daemon worker for the currently configured profile.