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