diff --git a/mhcflurry/parallelism.py b/mhcflurry/parallelism.py
index 5b04401c29c80e6f66b8aa34fa7cd9533afcff8a..88913986287c7694ceef2e506196612eb330a20e 100644
--- a/mhcflurry/parallelism.py
+++ b/mhcflurry/parallelism.py
@@ -221,7 +221,7 @@ def worker_init_entry_point(
 def worker_init(keras_backend=None, gpu_device_nums=None, worker_log_dir=None):
     if worker_log_dir:
         sys.stderr = sys.stdout = open(
-            os.path.join(worker_log_dir, "LOG-worker.%d.txt" % os.getpid(), "w"))
+            os.path.join(worker_log_dir, "LOG-worker.%d.txt" % os.getpid()), "w")
 
     # Each worker needs distinct random numbers
     numpy.random.seed()