@ ProgramNode (location: (0...32))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...32))
    └── body: (length: 1)
        └── @ CallNode (location: (0...32))
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── message_loc: (0...2) = "m1"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (3...11))
            │   └── arguments: (length: 1)
            │       └── @ KeywordHashNode (location: (3...11))
            │           └── elements: (length: 1)
            │               └── @ AssocNode (location: (3...11))
            │                   ├── key:
            │                   │   @ SymbolNode (location: (3...5))
            │                   │   ├── opening_loc: (3...4) = ":"
            │                   │   ├── value_loc: (4...5) = "k"
            │                   │   ├── closing_loc: ∅
            │                   │   └── unescaped: "k"
            │                   ├── value:
            │                   │   @ CallNode (location: (9...11))
            │                   │   ├── receiver: ∅
            │                   │   ├── call_operator_loc: ∅
            │                   │   ├── message_loc: (9...11) = "m2"
            │                   │   ├── opening_loc: ∅
            │                   │   ├── arguments: ∅
            │                   │   ├── closing_loc: ∅
            │                   │   ├── block: ∅
            │                   │   ├── flags: variable_call
            │                   │   └── name: "m2"
            │                   └── operator_loc: (6...8) = "=>"
            ├── closing_loc: ∅
            ├── block:
            │   @ BlockNode (location: (12...32))
            │   ├── locals: []
            │   ├── parameters: ∅
            │   ├── body:
            │   │   @ StatementsNode (location: (16...27))
            │   │   └── body: (length: 1)
            │   │       └── @ CallNode (location: (16...27))
            │   │           ├── receiver: ∅
            │   │           ├── call_operator_loc: ∅
            │   │           ├── message_loc: (16...18) = "m3"
            │   │           ├── opening_loc: (18...19) = "("
            │   │           ├── arguments: ∅
            │   │           ├── closing_loc: (19...20) = ")"
            │   │           ├── block:
            │   │           │   @ BlockNode (location: (21...27))
            │   │           │   ├── locals: []
            │   │           │   ├── parameters: ∅
            │   │           │   ├── body: ∅
            │   │           │   ├── opening_loc: (21...23) = "do"
            │   │           │   └── closing_loc: (24...27) = "end"
            │   │           ├── flags: ∅
            │   │           └── name: "m3"
            │   ├── opening_loc: (12...14) = "do"
            │   └── closing_loc: (29...32) = "end"
            ├── flags: ∅
            └── name: "m1"
