@ ProgramNode (location: (0...10))
├── locals: [:a]
└── statements:
    @ StatementsNode (location: (0...10))
    └── body: (length: 2)
        ├── @ LocalVariableWriteNode (location: (0...6))
        │   ├── name: :a
        │   ├── depth: 0
        │   ├── name_loc: (0...1) = "a"
        │   ├── value:
        │   │   @ IntegerNode (location: (4...6))
        │   │   └── flags: decimal
        │   └── operator_loc: (2...3) = "="
        └── @ CallNode (location: (7...10))
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── message_loc: (7...8) = "p"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (9...10))
            │   └── arguments: (length: 1)
            │       └── @ LocalVariableReadNode (location: (9...10))
            │           ├── name: :a
            │           └── depth: 0
            ├── closing_loc: ∅
            ├── block: ∅
            ├── flags: ∅
            └── name: "p"
