@ ProgramNode (location: (1,0)-(1,19))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,19))
    └── body: (length: 1)
        └── @ CallNode (location: (1,0)-(1,19))
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── name: :f
            ├── message_loc: (1,0)-(1,1) = "f"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (1,2)-(1,19))
            │   ├── arguments: (length: 1)
            │   │   └── @ LambdaNode (location: (1,2)-(1,19))
            │   │       ├── locals: []
            │   │       ├── locals_body_index: 0
            │   │       ├── operator_loc: (1,2)-(1,4) = "->"
            │   │       ├── opening_loc: (1,7)-(1,8) = "{"
            │   │       ├── closing_loc: (1,18)-(1,19) = "}"
            │   │       ├── parameters:
            │   │       │   @ BlockParametersNode (location: (1,4)-(1,6))
            │   │       │   ├── parameters: ∅
            │   │       │   ├── locals: (length: 0)
            │   │       │   ├── opening_loc: (1,4)-(1,5) = "("
            │   │       │   └── closing_loc: (1,5)-(1,6) = ")"
            │   │       └── body:
            │   │           @ StatementsNode (location: (1,9)-(1,17))
            │   │           └── body: (length: 1)
            │   │               └── @ CallNode (location: (1,9)-(1,17))
            │   │                   ├── receiver: ∅
            │   │                   ├── call_operator_loc: ∅
            │   │                   ├── name: :g
            │   │                   ├── message_loc: (1,9)-(1,10) = "g"
            │   │                   ├── opening_loc: ∅
            │   │                   ├── arguments: ∅
            │   │                   ├── closing_loc: ∅
            │   │                   ├── block:
            │   │                   │   @ BlockNode (location: (1,11)-(1,17))
            │   │                   │   ├── locals: []
            │   │                   │   ├── locals_body_index: 0
            │   │                   │   ├── parameters: ∅
            │   │                   │   ├── body: ∅
            │   │                   │   ├── opening_loc: (1,11)-(1,13) = "do"
            │   │                   │   └── closing_loc: (1,14)-(1,17) = "end"
            │   │                   └── flags: ∅
            │   └── flags: ∅
            ├── closing_loc: ∅
            ├── block: ∅
            └── flags: ∅