@ ProgramNode (location: (0...46))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...46))
    └── body: (length: 2)
        ├── @ UnlessNode (location: (0...24))
        │   ├── keyword_loc: (0...6) = "unless"
        │   ├── predicate:
        │   │   @ CallNode (location: (7...10))
        │   │   ├── receiver: ∅
        │   │   ├── call_operator_loc: ∅
        │   │   ├── message_loc: (7...10) = "foo"
        │   │   ├── opening_loc: ∅
        │   │   ├── arguments: ∅
        │   │   ├── closing_loc: ∅
        │   │   ├── block: ∅
        │   │   ├── flags: variable_call
        │   │   └── name: "foo"
        │   ├── statements:
        │   │   @ StatementsNode (location: (16...19))
        │   │   └── body: (length: 1)
        │   │       └── @ CallNode (location: (16...19))
        │   │           ├── receiver: ∅
        │   │           ├── call_operator_loc: ∅
        │   │           ├── message_loc: (16...19) = "bar"
        │   │           ├── opening_loc: ∅
        │   │           ├── arguments: ∅
        │   │           ├── closing_loc: ∅
        │   │           ├── block: ∅
        │   │           ├── flags: variable_call
        │   │           └── name: "bar"
        │   ├── consequent: ∅
        │   └── end_keyword_loc: (21...24) = "end"
        └── @ UnlessNode (location: (26...46))
            ├── keyword_loc: (26...32) = "unless"
            ├── predicate:
            │   @ CallNode (location: (33...36))
            │   ├── receiver: ∅
            │   ├── call_operator_loc: ∅
            │   ├── message_loc: (33...36) = "foo"
            │   ├── opening_loc: ∅
            │   ├── arguments: ∅
            │   ├── closing_loc: ∅
            │   ├── block: ∅
            │   ├── flags: variable_call
            │   └── name: "foo"
            ├── statements:
            │   @ StatementsNode (location: (38...41))
            │   └── body: (length: 1)
            │       └── @ CallNode (location: (38...41))
            │           ├── receiver: ∅
            │           ├── call_operator_loc: ∅
            │           ├── message_loc: (38...41) = "bar"
            │           ├── opening_loc: ∅
            │           ├── arguments: ∅
            │           ├── closing_loc: ∅
            │           ├── block: ∅
            │           ├── flags: variable_call
            │           └── name: "bar"
            ├── consequent: ∅
            └── end_keyword_loc: (43...46) = "end"
