diff --git a/kazoo/client.py b/kazoo/client.py
index 1830ca0b..d000688e 100644
--- a/kazoo/client.py
+++ b/kazoo/client.py
@@ -221,7 +221,9 @@ def __init__(
         self.logger = logger or log
 
         # Record the handler strategy used
-        self.handler = handler or SequentialThreadingHandler(logger=self.logger)
+        self.handler = handler
+        if not handler:
+            self.handler = SequentialThreadingHandler(logger=self.logger)
         if inspect.isclass(self.handler):
             raise ConfigurationError(
                 "Handler must be an instance of a class, "
diff --git a/kazoo/handlers/threading.py b/kazoo/handlers/threading.py
index be610878..83eebc51 100644
--- a/kazoo/handlers/threading.py
+++ b/kazoo/handlers/threading.py
@@ -110,6 +110,8 @@ def running(self):
         return self._running
 
     def _create_thread_worker(self, work_queue):
+        log = self.logger
+
         def _thread_worker():  # pragma: nocover
             while True:
                 try:
@@ -119,7 +121,7 @@ def _thread_worker():  # pragma: nocover
                             break
                         func()
                     except Exception:
-                        self.logger.exception("Exception in worker queue thread")
+                        log.exception("Exception in worker queue thread")
                     finally:
                         work_queue.task_done()
                         del func  # release before possible idle