@ ProgramNode (location: (1,0)-(3,1))
├── flags: ∅
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(3,1))
    ├── flags: ∅
    └── body: (length: 1)
        └── @ PreExecutionNode (location: (1,0)-(3,1))
            ├── flags: newline
            ├── statements:
            │   @ StatementsNode (location: (2,0)-(2,3))
            │   ├── flags: ∅
            │   └── body: (length: 1)
            │       └── @ CallNode (location: (2,0)-(2,3))
            │           ├── flags: newline, variable_call, ignore_visibility
            │           ├── receiver: ∅
            │           ├── call_operator_loc: ∅
            │           ├── name: :foo
            │           ├── message_loc: (2,0)-(2,3) = "foo"
            │           ├── opening_loc: ∅
            │           ├── arguments: ∅
            │           ├── closing_loc: ∅
            │           └── block: ∅
            ├── keyword_loc: (1,0)-(1,5) = "BEGIN"
            ├── opening_loc: (1,6)-(1,7) = "{"
            └── closing_loc: (3,0)-(3,1) = "}"
