@ ProgramNode (location: (1...9))
├── locals: [:a, :b]
└── statements:
    @ StatementsNode (location: (1...9))
    └── body: (length: 1)
        └── @ MultiWriteNode (location: (1...9))
            ├── targets: (length: 1)
            │   └── @ MultiTargetNode (location: (1...6))
            │       ├── targets: (length: 2)
            │       │   ├── @ LocalVariableTargetNode (location: (2...3))
            │       │   │   ├── name: :a
            │       │   │   └── depth: 0
            │       │   └── @ LocalVariableTargetNode (location: (4...5))
            │       │       ├── name: :b
            │       │       └── depth: 0
            │       ├── lparen_loc: (1...2) = "("
            │       └── rparen_loc: (5...6) = ")"
            ├── lparen_loc: ∅
            ├── rparen_loc: ∅
            ├── operator_loc: (7...8) = "="
            └── value:
                @ CallNode (location: (8...9))
                ├── receiver: ∅
                ├── call_operator_loc: ∅
                ├── message_loc: (8...9) = "c"
                ├── opening_loc: ∅
                ├── arguments: ∅
                ├── closing_loc: ∅
                ├── block: ∅
                ├── flags: variable_call
                └── name: "c"
