@ ProgramNode (location: (0...20))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...20))
    └── body: (length: 2)
        ├── @ IfNode (location: (0...9))
        │   ├── if_keyword_loc: ∅
        │   ├── predicate:
        │   │   @ CallNode (location: (0...1))
        │   │   ├── receiver: ∅
        │   │   ├── call_operator_loc: ∅
        │   │   ├── message_loc: (0...1) = "a"
        │   │   ├── opening_loc: ∅
        │   │   ├── arguments: ∅
        │   │   ├── closing_loc: ∅
        │   │   ├── block: ∅
        │   │   ├── flags: variable_call
        │   │   └── name: "a"
        │   ├── statements:
        │   │   @ StatementsNode (location: (4...6))
        │   │   └── body: (length: 1)
        │   │       └── @ StringNode (location: (4...6))
        │   │           ├── opening_loc: (4...5) = "\""
        │   │           ├── content_loc: (5...5) = ""
        │   │           ├── closing_loc: (5...6) = "\""
        │   │           └── unescaped: ""
        │   ├── consequent:
        │   │   @ ElseNode (location: (6...9))
        │   │   ├── else_keyword_loc: (6...7) = ":"
        │   │   ├── statements:
        │   │   │   @ StatementsNode (location: (8...9))
        │   │   │   └── body: (length: 1)
        │   │   │       └── @ CallNode (location: (8...9))
        │   │   │           ├── receiver: ∅
        │   │   │           ├── call_operator_loc: ∅
        │   │   │           ├── message_loc: (8...9) = "b"
        │   │   │           ├── opening_loc: ∅
        │   │   │           ├── arguments: ∅
        │   │   │           ├── closing_loc: ∅
        │   │   │           ├── block: ∅
        │   │   │           ├── flags: variable_call
        │   │   │           └── name: "b"
        │   │   └── end_keyword_loc: ∅
        │   └── end_keyword_loc: ∅
        └── @ IfNode (location: (11...20))
            ├── if_keyword_loc: ∅
            ├── predicate:
            │   @ CallNode (location: (11...12))
            │   ├── receiver: ∅
            │   ├── call_operator_loc: ∅
            │   ├── message_loc: (11...12) = "a"
            │   ├── opening_loc: ∅
            │   ├── arguments: ∅
            │   ├── closing_loc: ∅
            │   ├── block: ∅
            │   ├── flags: variable_call
            │   └── name: "a"
            ├── statements:
            │   @ StatementsNode (location: (15...17))
            │   └── body: (length: 1)
            │       └── @ StringNode (location: (15...17))
            │           ├── opening_loc: (15...16) = "'"
            │           ├── content_loc: (16...16) = ""
            │           ├── closing_loc: (16...17) = "'"
            │           └── unescaped: ""
            ├── consequent:
            │   @ ElseNode (location: (17...20))
            │   ├── else_keyword_loc: (17...18) = ":"
            │   ├── statements:
            │   │   @ StatementsNode (location: (19...20))
            │   │   └── body: (length: 1)
            │   │       └── @ CallNode (location: (19...20))
            │   │           ├── receiver: ∅
            │   │           ├── call_operator_loc: ∅
            │   │           ├── message_loc: (19...20) = "b"
            │   │           ├── opening_loc: ∅
            │   │           ├── arguments: ∅
            │   │           ├── closing_loc: ∅
            │   │           ├── block: ∅
            │   │           ├── flags: variable_call
            │   │           └── name: "b"
            │   └── end_keyword_loc: ∅
            └── end_keyword_loc: ∅
