@ ProgramNode (location: (1,0)-(5,13))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(5,13))
    └── body: (length: 3)
        ├── @ LambdaNode (location: (1,0)-(1,12))
        │   ├── locals: []
        │   ├── operator_loc: (1,0)-(1,2) = "->"
        │   ├── opening_loc: (1,10)-(1,11) = "{"
        │   ├── closing_loc: (1,11)-(1,12) = "}"
        │   ├── parameters:
        │   │   @ BlockParametersNode (location: (1,2)-(1,9))
        │   │   ├── parameters:
        │   │   │   @ ParametersNode (location: (1,3)-(1,8))
        │   │   │   ├── requireds: (length: 0)
        │   │   │   ├── optionals: (length: 0)
        │   │   │   ├── rest: ∅
        │   │   │   ├── posts: (length: 0)
        │   │   │   ├── keywords: (length: 0)
        │   │   │   ├── keyword_rest:
        │   │   │   │   @ NoKeywordsParameterNode (location: (1,3)-(1,8))
        │   │   │   │   ├── operator_loc: (1,3)-(1,5) = "**"
        │   │   │   │   └── keyword_loc: (1,5)-(1,8) = "nil"
        │   │   │   └── block: ∅
        │   │   ├── locals: (length: 0)
        │   │   ├── opening_loc: (1,2)-(1,3) = "("
        │   │   └── closing_loc: (1,8)-(1,9) = ")"
        │   └── body: ∅
        ├── @ DefNode (location: (3,0)-(3,17))
        │   ├── name: :f
        │   ├── name_loc: (3,4)-(3,5) = "f"
        │   ├── receiver: ∅
        │   ├── parameters:
        │   │   @ ParametersNode (location: (3,6)-(3,11))
        │   │   ├── requireds: (length: 0)
        │   │   ├── optionals: (length: 0)
        │   │   ├── rest: ∅
        │   │   ├── posts: (length: 0)
        │   │   ├── keywords: (length: 0)
        │   │   ├── keyword_rest:
        │   │   │   @ NoKeywordsParameterNode (location: (3,6)-(3,11))
        │   │   │   ├── operator_loc: (3,6)-(3,8) = "**"
        │   │   │   └── keyword_loc: (3,8)-(3,11) = "nil"
        │   │   └── block: ∅
        │   ├── body: ∅
        │   ├── locals: []
        │   ├── def_keyword_loc: (3,0)-(3,3) = "def"
        │   ├── operator_loc: ∅
        │   ├── lparen_loc: (3,5)-(3,6) = "("
        │   ├── rparen_loc: (3,11)-(3,12) = ")"
        │   ├── equal_loc: ∅
        │   └── end_keyword_loc: (3,14)-(3,17) = "end"
        └── @ CallNode (location: (5,0)-(5,13))
            ├── flags: ignore_visibility
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── name: :m
            ├── message_loc: (5,0)-(5,1) = "m"
            ├── opening_loc: ∅
            ├── arguments: ∅
            ├── closing_loc: ∅
            └── block:
                @ BlockNode (location: (5,2)-(5,13))
                ├── locals: []
                ├── parameters:
                │   @ BlockParametersNode (location: (5,4)-(5,11))
                │   ├── parameters:
                │   │   @ ParametersNode (location: (5,5)-(5,10))
                │   │   ├── requireds: (length: 0)
                │   │   ├── optionals: (length: 0)
                │   │   ├── rest: ∅
                │   │   ├── posts: (length: 0)
                │   │   ├── keywords: (length: 0)
                │   │   ├── keyword_rest:
                │   │   │   @ NoKeywordsParameterNode (location: (5,5)-(5,10))
                │   │   │   ├── operator_loc: (5,5)-(5,7) = "**"
                │   │   │   └── keyword_loc: (5,7)-(5,10) = "nil"
                │   │   └── block: ∅
                │   ├── locals: (length: 0)
                │   ├── opening_loc: (5,4)-(5,5) = "|"
                │   └── closing_loc: (5,10)-(5,11) = "|"
                ├── body: ∅
                ├── opening_loc: (5,2)-(5,3) = "{"
                └── closing_loc: (5,12)-(5,13) = "}"