@ ProgramNode (location: (1,0)-(1,10))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,10))
    └── body: (length: 1)
        └── @ StringNode (location: (1,0)-(1,10))
            ├── flags: ∅
            ├── opening_loc: (1,0)-(1,10) = "<<-HEREDOC"
            ├── content_loc: (2,0)-(3,0) = "\#${\n"
            ├── closing_loc: (3,0)-(4,0) = "HEREDOC\n"
            └── unescaped: "\#${\n"