diff --git a/Lib/sets.py b/Lib/sets.py
index 5ca85de..09d9918 100644
--- a/Lib/sets.py
+++ b/Lib/sets.py
@@ -363,15 +363,17 @@
 
     # In-place union, intersection, differences
 
-    def union_update(self, other):
+    def __ior__(self, other):
         """Update a set with the union of itself and another."""
         self._binary_sanity_check(other)
         self._data.update(other._data)
         return self
 
-    __ior__ = union_update
+    def union_update(self, other):
+        """Update a set with the union of itself and another."""
+        self |= other
 
-    def intersection_update(self, other):
+    def __iand__(self, other):
         """Update a set with the intersection of itself and another."""
         self._binary_sanity_check(other)
         for elt in self._data.keys():
@@ -379,9 +381,11 @@
                 del self._data[elt]
         return self
 
-    __iand__ = intersection_update
+    def intersection_update(self, other):
+        """Update a set with the intersection of itself and another."""
+        self &= other
 
-    def symmetric_difference_update(self, other):
+    def __ixor__(self, other):
         """Update a set with the symmetric difference of itself and another."""
         self._binary_sanity_check(other)
         data = self._data
@@ -393,9 +397,11 @@
                 data[elt] = value
         return self
 
-    __ixor__ = symmetric_difference_update
+    def symmetric_difference_update(self, other):
+        """Update a set with the symmetric difference of itself and another."""
+        self ^= other
 
-    def difference_update(self, other):
+    def __isub__(self, other):
         """Remove all elements of another set from this set."""
         self._binary_sanity_check(other)
         data = self._data
@@ -404,7 +410,9 @@
                 del data[elt]
         return self
 
-    __isub__ = difference_update
+    def difference_update(self, other):
+        """Remove all elements of another set from this set."""
+        self -= other
 
     # Python dict-like mass mutations: update, clear
 
diff --git a/Lib/test/test_sets.py b/Lib/test/test_sets.py
index b56219b..9ff98a6 100644
--- a/Lib/test/test_sets.py
+++ b/Lib/test/test_sets.py
@@ -219,6 +219,10 @@
         self.set |= Set([8])
         assert self.set == Set([2, 4, 6, 8]), "Non-overlapping union"
 
+    def test_union_method_call(self):
+        self.set.union_update(Set([3, 4, 5]))
+        assert self.set == Set([2, 3, 4, 5, 6]), "Union method call"
+
     def test_intersection_subset(self):
         self.set &= Set((2, 4))
         assert self.set == Set((2, 4)), "Subset intersection"
@@ -235,6 +239,10 @@
         self.set &= Set([8])
         assert self.set == empty_set, "Non-overlapping intersection"
 
+    def test_intersection_method_call(self):
+        self.set.intersection_update(Set([3, 4, 5]))
+        assert self.set == Set([4]), "Intersection method call"
+
     def test_sym_difference_subset(self):
         self.set ^= Set((2, 4))
         assert self.set == Set([6]), "Subset symmetric difference"
@@ -251,6 +259,30 @@
         self.set ^= Set([8])
         assert self.set == Set([2, 4, 6, 8]), "Non-overlapping symmetric difference"
 
+    def test_sym_difference_method_call(self):
+        self.set.symmetric_difference_update(Set([3, 4, 5]))
+        assert self.set == Set([2, 3, 5, 6]), "Symmetric difference method call"
+
+    def test_difference_subset(self):
+        self.set -= Set((2, 4))
+        assert self.set == Set([6]), "Subset difference"
+
+    def test_difference_superset(self):
+        self.set -= Set((2, 4, 6, 8))
+        assert self.set == Set([]), "Superset difference"
+
+    def test_difference_overlap(self):
+        self.set -= Set((3, 4, 5))
+        assert self.set == Set([2, 6]), "Overlapping difference"
+
+    def test_difference_non_overlap(self):
+        self.set -= Set([8])
+        assert self.set == Set([2, 4, 6]), "Non-overlapping difference"
+
+    def test_difference_method_call(self):
+        self.set.difference_update(Set([3, 4, 5]))
+        assert self.set == Set([2, 6]), "Difference method call"
+
 #==============================================================================
 
 class TestMutate(unittest.TestCase):