diff -r 57875cf423c9 -r 2372284d9457 tests/test-extensions-wrapfunction.py
--- a/tests/test-extensions-wrapfunction.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/tests/test-extensions-wrapfunction.py	Sun Oct 06 09:45:02 2019 -0400
@@ -2,28 +2,36 @@
 
 from mercurial import extensions
 
+
 def genwrapper(x):
     def f(orig, *args, **kwds):
         return [x] + orig(*args, **kwds)
+
     f.x = x
     return f
 
+
 def getid(wrapper):
     return getattr(wrapper, 'x', '-')
 
+
 wrappers = [genwrapper(i) for i in range(5)]
 
+
 class dummyclass(object):
     def getstack(self):
         return ['orig']
 
+
 dummy = dummyclass()
 
+
 def batchwrap(wrappers):
     for w in wrappers:
         extensions.wrapfunction(dummy, 'getstack', w)
         print('wrap %d: %s' % (getid(w), dummy.getstack()))
 
+
 def batchunwrap(wrappers):
     for w in wrappers:
         result = None
@@ -34,9 +42,14 @@
             msg = e.__class__.__name__
         print('unwrap %s: %s: %s' % (getid(w), getid(result), msg))
 
+
 batchwrap(wrappers + [wrappers[0]])
-batchunwrap([(wrappers[i] if i is not None and i >= 0 else None)
-             for i in [3, None, 0, 4, 0, 2, 1, None]])
+batchunwrap(
+    [
+        (wrappers[i] if i is not None and i >= 0 else None)
+        for i in [3, None, 0, 4, 0, 2, 1, None]
+    ]
+)
 
 wrap0 = extensions.wrappedfunction(dummy, 'getstack', wrappers[0])
 wrap1 = extensions.wrappedfunction(dummy, 'getstack', wrappers[1])
@@ -59,6 +72,8 @@
 class callableobj(object):
     def __call__(self):
         return ['orig']
+
+
 dummy.cobj = callableobj()
 extensions.wrapfunction(dummy, 'cobj', wrappers[0])
 print('wrap callable object', dummy.cobj())