changing "default" for exception_handlers to None; same exact logic can be implemented, but cleaner

rq/worker.py

@@ -122,7 +122,7 @@ class Worker(object):
 
     def __init__(self, queues, name=None,
                  default_result_ttl=None, connection=None,
-                 exception_handlers="default", default_worker_ttl=None, job_class=None):  # noqa
+                 exception_handlers=None, default_worker_ttl=None, job_class=None):  # noqa
         if connection is None:
             connection = get_current_connection()
         self.connection = connection
@@ -150,7 +150,7 @@ class Worker(object):
 
         # By default, push the "move-to-failed-queue" exception handler onto
         # the stack
-        if exception_handlers == "default":
+        if exception_handlers is None:
             self.push_exc_handler(self.move_to_failed_queue)
         elif isinstance(exception_handlers, list):
             for h in exception_handlers: