@ ProgramNode (location: (6...74))
├── locals: [:string]
└── statements:
    @ StatementsNode (location: (6...74))
    └── body: (length: 2)
        ├── @ LocalVariableWriteNode (location: (6...22))
        │   ├── name: :string
        │   ├── depth: 0
        │   ├── name_loc: (6...12) = "string"
        │   ├── value:
        │   │   @ StringNode (location: (15...22))
        │   │   ├── opening_loc: (15...22) = "<<-\"^D\""
        │   │   ├── content_loc: (23...48) = "        very long string\n"
        │   │   ├── closing_loc: (48...57) = "      ^D\n"
        │   │   └── unescaped: "        very long string\n"
        │   └── operator_loc: (13...14) = "="
        └── @ CallNode (location: (63...74))
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── message_loc: (63...67) = "puts"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (68...74))
            │   └── arguments: (length: 1)
            │       └── @ LocalVariableReadNode (location: (68...74))
            │           ├── name: :string
            │           └── depth: 0
            ├── closing_loc: ∅
            ├── block: ∅
            ├── flags: ∅
            └── name: "puts"
