@ ProgramNode (location: (0...20))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...20))
    └── body: (length: 1)
        └── @ BeginNode (location: (0...20))
            ├── begin_keyword_loc: (0...5) = "begin"
            ├── statements:
            │   @ StatementsNode (location: (6...16))
            │   └── body: (length: 2)
            │       ├── @ CallNode (location: (6...10))
            │       │   ├── receiver: ∅
            │       │   ├── call_operator_loc: ∅
            │       │   ├── message_loc: (6...10) = "foo!"
            │       │   ├── opening_loc: ∅
            │       │   ├── arguments: ∅
            │       │   ├── closing_loc: ∅
            │       │   ├── block: ∅
            │       │   ├── flags: ∅
            │       │   └── name: "foo!"
            │       └── @ CallNode (location: (12...16))
            │           ├── receiver: ∅
            │           ├── call_operator_loc: ∅
            │           ├── message_loc: (12...16) = "bar!"
            │           ├── opening_loc: ∅
            │           ├── arguments: ∅
            │           ├── closing_loc: ∅
            │           ├── block: ∅
            │           ├── flags: ∅
            │           └── name: "bar!"
            ├── rescue_clause: ∅
            ├── else_clause: ∅
            ├── ensure_clause: ∅
            └── end_keyword_loc: (17...20) = "end"
