@ ProgramNode (location: (0...26))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...26))
    └── body: (length: 1)
        └── @ DefNode (location: (0...26))
            ├── name: :fun
            ├── name_loc: (4...7) = "fun"
            ├── receiver: ∅
            ├── parameters:
            │   @ ParametersNode (location: (8...16))
            │   ├── requireds: (length: 0)
            │   ├── optionals: (length: 0)
            │   ├── rest: ∅
            │   ├── posts: (length: 0)
            │   ├── keywords: (length: 1)
            │   │   └── @ KeywordParameterNode (location: (8...16))
            │   │       ├── name: :kw
            │   │       ├── name_loc: (8...11) = "kw:"
            │   │       └── value:
            │   │           @ SymbolNode (location: (12...16))
            │   │           ├── opening_loc: (12...13) = ":"
            │   │           ├── value_loc: (13...16) = "val"
            │   │           ├── closing_loc: ∅
            │   │           └── unescaped: "val"
            │   ├── keyword_rest: ∅
            │   └── block: ∅
            ├── body:
            │   @ StatementsNode (location: (19...21))
            │   └── body: (length: 1)
            │       └── @ LocalVariableReadNode (location: (19...21))
            │           ├── name: :kw
            │           └── depth: 0
            ├── locals: [:kw]
            ├── def_keyword_loc: (0...3) = "def"
            ├── operator_loc: ∅
            ├── lparen_loc: (7...8) = "("
            ├── rparen_loc: (16...17) = ")"
            ├── equal_loc: ∅
            └── end_keyword_loc: (23...26) = "end"
