@ ProgramNode (location: (0...8))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...8))
    └── body: (length: 2)
        ├── @ StringNode (location: (0...6))
        │   ├── opening_loc: (0...1) = "\""
        │   ├── content_loc: (1...5) = "a\\nb"
        │   ├── closing_loc: (5...6) = "\""
        │   └── unescaped: "a\nb"
        └── @ IntegerNode (location: (7...8))
            └── flags: decimal
