ProgramNode(0...20)(
  [],
  StatementsNode(0...20)(
    [DefNode(0...20)(
       (9...15),
       SelfNode(4...8)(),
       nil,
       nil,
       [],
       (0...3),
       (8...9),
       nil,
       nil,
       nil,
       (17...20)
     )]
  )
)
