@ ProgramNode (location: (0...28))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...28))
    └── body: (length: 1)
        └── @ CallNode (location: (0...28))
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── message_loc: (0...1) = "p"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (2...21))
            │   └── arguments: (length: 2)
            │       ├── @ LambdaNode (location: (2...15))
            │       │   ├── locals: []
            │       │   ├── operator_loc: (2...4) = "->"
            │       │   ├── opening_loc: (5...6) = "{"
            │       │   ├── closing_loc: (14...15) = "}"
            │       │   ├── parameters: ∅
            │       │   └── body:
            │       │       @ StatementsNode (location: (7...13))
            │       │       └── body: (length: 1)
            │       │           └── @ SymbolNode (location: (7...13))
            │       │               ├── opening_loc: (7...8) = ":"
            │       │               ├── value_loc: (8...13) = "hello"
            │       │               ├── closing_loc: ∅
            │       │               └── unescaped: "hello"
            │       └── @ KeywordHashNode (location: (17...21))
            │           └── elements: (length: 1)
            │               └── @ AssocNode (location: (17...21))
            │                   ├── key:
            │                   │   @ SymbolNode (location: (17...19))
            │                   │   ├── opening_loc: ∅
            │                   │   ├── value_loc: (17...18) = "a"
            │                   │   ├── closing_loc: (18...19) = ":"
            │                   │   └── unescaped: "a"
            │                   ├── value:
            │                   │   @ IntegerNode (location: (20...21))
            │                   │   └── flags: decimal
            │                   └── operator_loc: ∅
            ├── closing_loc: ∅
            ├── block:
            │   @ BlockNode (location: (22...28))
            │   ├── locals: []
            │   ├── parameters: ∅
            │   ├── body: ∅
            │   ├── opening_loc: (22...24) = "do"
            │   └── closing_loc: (25...28) = "end"
            ├── flags: ∅
            └── name: "p"
