SF patch 1547796 by Georg Brandl -- set literals.
diff --git a/Lib/compiler/ast.py b/Lib/compiler/ast.py
index 94a6262..6953325 100644
--- a/Lib/compiler/ast.py
+++ b/Lib/compiler/ast.py
@@ -542,7 +542,6 @@
             self.kwargs = 1
 
 
-
     def getChildren(self):
         children = []
         children.append(self.decorators)
@@ -572,6 +571,7 @@
         self.argnames = ['.0']
         self.varargs = self.kwargs = None
 
+
     def getChildren(self):
         return self.code,
 
@@ -589,7 +589,6 @@
         self.lineno = lineno
         self.is_outmost = False
 
-
     def getChildren(self):
         children = []
         children.append(self.assign)
@@ -766,7 +765,6 @@
             self.kwargs = 1
 
 
-
     def getChildren(self):
         children = []
         children.append(self.argnames)
@@ -1091,6 +1089,22 @@
     def __repr__(self):
         return "RightShift((%s, %s))" % (repr(self.left), repr(self.right))
 
+class Set(Node):
+    def __init__(self, items, lineno=None):
+        self.items = items
+        self.lineno = lineno
+
+    def getChildren(self):
+        return tuple(flatten(self.items))
+
+    def getChildNodes(self):
+        nodelist = []
+        nodelist.extend(flatten_nodes(self.items))
+        return tuple(nodelist)
+
+    def __repr__(self):
+        return "Set(%s)" % (repr(self.items),)
+
 class Slice(Node):
     def __init__(self, expr, flags, lower, upper, lineno=None):
         self.expr = expr