@ ProgramNode (location: (1,0)-(1,12))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,12))
    └── body: (length: 1)
        └── @ CallNode (location: (1,0)-(1,12))
            ├── flags: ignore_visibility
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── name: :puts
            ├── message_loc: (1,0)-(1,4) = "puts"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (1,5)-(1,12))
            │   ├── flags: ∅
            │   └── arguments: (length: 1)
            │       └── @ KeywordHashNode (location: (1,5)-(1,12))
            │           ├── flags: symbol_keys
            │           └── elements: (length: 1)
            │               └── @ AssocNode (location: (1,5)-(1,12))
            │                   ├── key:
            │                   │   @ SymbolNode (location: (1,5)-(1,9))
            │                   │   ├── flags: forced_us_ascii_encoding
            │                   │   ├── opening_loc: (1,5)-(1,6) = "'"
            │                   │   ├── value_loc: (1,6)-(1,7) = "a"
            │                   │   ├── closing_loc: (1,7)-(1,9) = "':"
            │                   │   └── unescaped: "a"
            │                   ├── value:
            │                   │   @ HashNode (location: (1,10)-(1,12))
            │                   │   ├── opening_loc: (1,10)-(1,11) = "{"
            │                   │   ├── elements: (length: 0)
            │                   │   └── closing_loc: (1,11)-(1,12) = "}"
            │                   └── operator_loc: ∅
            ├── closing_loc: ∅
            └── block: ∅