ProgramNode(0...10)(
  [],
  StatementsNode(0...10)(
    [InterpolatedStringNode(0...10)(
       (0...1),
       [StringNode(1...3)(nil, (1...3), nil, "a "),
        EmbeddedStatementsNode(3...9)(
          (3...5),
          StatementsNode(5...8)(
            [StringNode(5...8)((5...6), (6...7), (7...8), "b")]
          ),
          (8...9)
        )],
       (9...10)
     )]
  )
)
