diff --git a/lib/spack/spack/stage.py b/lib/spack/spack/stage.py
index 62bb391f541..79f43730973 100644
--- a/lib/spack/spack/stage.py
+++ b/lib/spack/spack/stage.py
@@ -212,7 +212,7 @@ def __init__(
             if self.name not in Stage.stage_locks:
                 sha1 = hashlib.sha1(self.name.encode('utf-8')).digest()
                 lock_id = prefix_bits(sha1, bit_length(sys.maxsize))
-                stage_lock_path = os.path.join(spack.paths.stage_path,'.lock')
+                stage_lock_path = os.path.join(spack.paths.stage_path, '.lock')
                 Stage.stage_locks[self.name] = spack.util.lock.Lock(
                     stage_lock_path, lock_id, 1)