@ ProgramNode (location: (0...23))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...23))
    └── body: (length: 1)
        └── @ CallNode (location: (0...23))
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── message_loc: (0...1) = "f"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (2...10))
            │   └── arguments: (length: 1)
            │       └── @ StringNode (location: (2...10))
            │           ├── opening_loc: (2...10) = "<<-TABLE"
            │           ├── content_loc: (10...14) = " do\n"
            │           ├── closing_loc: (14...20) = "TABLE\n"
            │           └── unescaped: ""
            ├── closing_loc: ∅
            ├── block:
            │   @ BlockNode (location: (11...23))
            │   ├── locals: []
            │   ├── parameters: ∅
            │   ├── body: ∅
            │   ├── opening_loc: (11...13) = "do"
            │   └── closing_loc: (20...23) = "end"
            ├── flags: ∅
            └── name: "f"
