func list1() (*ast.ListCell, *ast.ListCell) {
l0 := ast.NewList()
l0.Add(ast.NewSym("+"))
l0.Add(ast.NewSym("x"))
l1 := l0.Add(ast.NewList()).(*ast.ListCell)
l1.Add(ast.NewSym("*"))
l1.Add(ast.NewNum(4))
l1.Add(ast.NewNum(7))
l0.Add(ast.NewNum(1))
return l0, l1
}
func list2() (*ast.ListCell,
*ast.ListCell,
*ast.ListCell,
*ast.ListCell,
*ast.ListCell) {
// l0 is the top list, l1 and l2 are elements of l0
// l3 and l4 are elements of l2
l0 := ast.NewList()
l0.Add(ast.NewNum(3))
l1 := l0.Add(ast.NewList()).(*ast.ListCell)
l2 := l0.Add(ast.NewList()).(*ast.ListCell)
l3 := l2.Add(ast.NewList()).(*ast.ListCell)
l2.Add(ast.NewSym("g"))
l4 := l2.Add(ast.NewList()).(*ast.ListCell)
return l0, l1, l2, l3, l4
}