diff --git a/metaflow/multicore_utils.py b/metaflow/multicore_utils.py
index 55704623d5b..6e79c20ada5 100644
--- a/metaflow/multicore_utils.py
+++ b/metaflow/multicore_utils.py
@@ -60,7 +60,6 @@ def _spawn(func, arg, dir):
 
 
 def parallel_imap_unordered(func, iterable, max_parallel=None, dir=None):
-
     if max_parallel is None:
         max_parallel = cpu_count()
 
@@ -68,7 +67,6 @@ def parallel_imap_unordered(func, iterable, max_parallel=None, dir=None):
     pids = [_spawn(func, arg, dir) for arg in islice(args_iter, max_parallel)]
 
     while pids:
-
         for idx, pid_info in enumerate(pids):
             pid, output_file = pid_info
             pid, exit_code = os.waitpid(pid, os.WNOHANG)
diff --git a/test/unit/test_multicore_utils.py b/test/unit/test_multicore_utils.py
index db5b9edfa93..9b14a20b99a 100644
--- a/test/unit/test_multicore_utils.py
+++ b/test/unit/test_multicore_utils.py
@@ -2,4 +2,11 @@
 
 
 def test_parallel_map():
-    assert parallel_map(lambda s: s.upper(), ['a', 'b', 'c', 'd', 'e', 'f']) == ['A', 'B', 'C', 'D', 'E', 'F']
+    assert parallel_map(lambda s: s.upper(), ["a", "b", "c", "d", "e", "f"]) == [
+        "A",
+        "B",
+        "C",
+        "D",
+        "E",
+        "F",
+    ]