ProgramNode(0...4)(
  [],
  StatementsNode(0...4)(
    [CallNode(0...4)(
       CallNode(0...1)(nil, nil, (0...1), nil, nil, nil, nil, 0, "a"),
       (1...3),
       (3...4),
       nil,
       nil,
       nil,
       nil,
       1,
       "b"
     )]
  )
)
