@ ProgramNode (location: (1,0)-(7,11))
├── flags: ∅
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(7,11))
    ├── flags: ∅
    └── body: (length: 4)
        ├── @ ReturnNode (location: (1,0)-(1,6))
        │   ├── flags: newline
        │   ├── keyword_loc: (1,0)-(1,6) = "return"
        │   └── arguments: ∅
        ├── @ ReturnNode (location: (3,0)-(3,10))
        │   ├── flags: newline
        │   ├── keyword_loc: (3,0)-(3,6) = "return"
        │   └── arguments:
        │       @ ArgumentsNode (location: (3,7)-(3,10))
        │       ├── flags: ∅
        │       └── arguments: (length: 1)
        │           └── @ CallNode (location: (3,7)-(3,10))
        │               ├── flags: variable_call, ignore_visibility
        │               ├── receiver: ∅
        │               ├── call_operator_loc: ∅
        │               ├── name: :foo
        │               ├── message_loc: (3,7)-(3,10) = "foo"
        │               ├── opening_loc: ∅
        │               ├── arguments: ∅
        │               ├── closing_loc: ∅
        │               └── block: ∅
        ├── @ ReturnNode (location: (5,0)-(5,8))
        │   ├── flags: newline
        │   ├── keyword_loc: (5,0)-(5,6) = "return"
        │   └── arguments:
        │       @ ArgumentsNode (location: (5,6)-(5,8))
        │       ├── flags: ∅
        │       └── arguments: (length: 1)
        │           └── @ ParenthesesNode (location: (5,6)-(5,8))
        │               ├── flags: ∅
        │               ├── body: ∅
        │               ├── opening_loc: (5,6)-(5,7) = "("
        │               └── closing_loc: (5,7)-(5,8) = ")"
        └── @ ReturnNode (location: (7,0)-(7,11))
            ├── flags: newline
            ├── keyword_loc: (7,0)-(7,6) = "return"
            └── arguments:
                @ ArgumentsNode (location: (7,6)-(7,11))
                ├── flags: ∅
                └── arguments: (length: 1)
                    └── @ ParenthesesNode (location: (7,6)-(7,11))
                        ├── flags: ∅
                        ├── body:
                        │   @ StatementsNode (location: (7,7)-(7,10))
                        │   ├── flags: ∅
                        │   └── body: (length: 1)
                        │       └── @ CallNode (location: (7,7)-(7,10))
                        │           ├── flags: newline, variable_call, ignore_visibility
                        │           ├── receiver: ∅
                        │           ├── call_operator_loc: ∅
                        │           ├── name: :foo
                        │           ├── message_loc: (7,7)-(7,10) = "foo"
                        │           ├── opening_loc: ∅
                        │           ├── arguments: ∅
                        │           ├── closing_loc: ∅
                        │           └── block: ∅
                        ├── opening_loc: (7,6)-(7,7) = "("
                        └── closing_loc: (7,10)-(7,11) = ")"
