1 files changed, 10 insertions, 7 deletions
diff --git a/tests/thread/mutate_instance.py b/tests/thread/mutate_instance.py
index a1ae428b5..939a0b8ac 100644
--- a/tests/thread/mutate_instance.py
+++ b/tests/thread/mutate_instance.py
@@ -7,25 +7,28 @@ import _thread
 # the shared user class and instance
 class User:
     def __init__(self):
-        self.a = 'A'
-        self.b = 'B'
-        self.c = 'C'
+        self.a = "A"
+        self.b = "B"
+        self.c = "C"
+
+
 user = User()
 
 # main thread function
 def th(n, lo, hi):
     for repeat in range(n):
         for i in range(lo, hi):
-            setattr(user, 'attr_%u' % i, repeat + i)
-            assert getattr(user, 'attr_%u' % i) == repeat + i
+            setattr(user, "attr_%u" % i, repeat + i)
+            assert getattr(user, "attr_%u" % i) == repeat + i
 
     with lock:
         global n_finished
         n_finished += 1
 
+
 lock = _thread.allocate_lock()
 n_repeat = 30
-n_range = 50 # 300 for stressful test (uses more heap)
+n_range = 50  # 300 for stressful test (uses more heap)
 n_thread = 4
 n_finished = 0
 
@@ -40,4 +43,4 @@ while n_finished < n_thread:
 # check user instance has correct contents
 print(user.a, user.b, user.c)
 for i in range(n_thread * n_range):
-    assert getattr(user, 'attr_%u' % i) == n_repeat - 1 + i
+    assert getattr(user, "attr_%u" % i) == n_repeat - 1 + i