@ ProgramNode (location: (0...6))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...6))
    └── body: (length: 1)
        └── @ StringNode (location: (0...6))
            ├── opening_loc: (0...6) = "<<-END"
            ├── content_loc: (6...7) = "\n"
            ├── closing_loc: (7...10) = "END"
            └── unescaped: ""
