def ssa(node):
    unroller = ASTUnroller()
    walk(node, unroller)
    node = unroller.unrolled_node[node]
    v = SSAVisitor()
    walk(node, v)
    return FlattenVisitor.flatten(v.ssa_node[node])
def ssa(node):
    unroller = ASTUnroller()
    walk(node, unroller)
    node = unroller.unrolled_node[node]
    v = SSAVisitor()
    walk(node, v)
    return FlattenVisitor.flatten(v.ssa_node[node])