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