@ ProgramNode (location: (0...6))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...6))
    └── body: (length: 1)
        └── @ HashNode (location: (0...6))
            ├── opening_loc: (0...1) = "{"
            ├── elements: (length: 1)
            │   └── @ AssocNode (location: (2...4))
            │       ├── key:
            │       │   @ SymbolNode (location: (2...4))
            │       │   ├── opening_loc: ∅
            │       │   ├── value_loc: (2...3) = "y"
            │       │   ├── closing_loc: (3...4) = ":"
            │       │   └── unescaped: "y"
            │       ├── value: ∅
            │       └── operator_loc: ∅
            └── closing_loc: (5...6) = "}"
