@ ProgramNode (location: (1,6)-(5,9))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,6)-(5,9))
    └── body: (length: 1)
        └── @ DefNode (location: (1,6)-(5,9))
            ├── name: :blah
            ├── name_loc: (1,10)-(1,14) = "blah"
            ├── receiver: ∅
            ├── parameters: ∅
            ├── body:
            │   @ StatementsNode (location: (2,8)-(4,11))
            │   └── body: (length: 1)
            │       └── @ IfNode (location: (2,8)-(4,11))
            │           ├── if_keyword_loc: (2,8)-(2,10) = "if"
            │           ├── predicate:
            │           │   @ TrueNode (location: (2,11)-(2,15))
            │           ├── then_keyword_loc: (2,16)-(2,20) = "then"
            │           ├── statements:
            │           │   @ StatementsNode (location: (3,10)-(3,19))
            │           │   └── body: (length: 1)
            │           │       └── @ ReturnNode (location: (3,10)-(3,19))
            │           │           ├── flags: redundant
            │           │           ├── keyword_loc: (3,10)-(3,16) = "return"
            │           │           └── arguments:
            │           │               @ ArgumentsNode (location: (3,17)-(3,19))
            │           │               ├── flags: ∅
            │           │               └── arguments: (length: 1)
            │           │                   └── @ IntegerNode (location: (3,17)-(3,19))
            │           │                       ├── flags: decimal
            │           │                       └── value: 42
            │           ├── consequent: ∅
            │           └── end_keyword_loc: (4,8)-(4,11) = "end"
            ├── locals: []
            ├── def_keyword_loc: (1,6)-(1,9) = "def"
            ├── operator_loc: ∅
            ├── lparen_loc: ∅
            ├── rparen_loc: ∅
            ├── equal_loc: ∅
            └── end_keyword_loc: (5,6)-(5,9) = "end"