fix lint error

Author: prakashsellathurai

Lib/test/test_weakref.py

@@ -542,52 +542,52 @@ def test_proxy_unref_add_refcount(self):
         class C:
             def __add__(self, o):
                 return NotImplemented
-        
+
         # create dead proxy
         o = C()
         dead = weakref.proxy(o)
         del o
         gc.collect()
-    
+
         # create live proxy
         obj = C()
         ref = weakref.ref(obj)
         proxy = weakref.proxy(obj)
-        
+
         try:
             operator.add(proxy, dead)
         except ReferenceError:
             pass
-    
+
         del proxy, obj, dead
         gc.collect()
-    
+
         self.assertIsNone(ref(), "Leaked object in add operation")
-    
+
     def test_proxy_unref_pow_refcount(self):
         class C:
             def __pow__(self, o, m=None):
                 return NotImplemented
-    
+
         # create dead proxy
         o = C()
         dead = weakref.proxy(o)
         del o
         gc.collect()
-    
+
         # create live proxy
         obj = C()
         ref = weakref.ref(obj)
         proxy = weakref.proxy(obj)
-    
+
         try:
             pow(proxy, dead, None)
         except ReferenceError:
             pass
-    
+
         del proxy, obj, dead
         gc.collect()
-    
+
         self.assertIsNone(ref(), "Leaked object in pow operation")
 
     def test_getweakrefcount(self):