@ ProgramNode (location: (1,0)-(4,3))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(4,3))
    └── body: (length: 1)
        └── @ CaseMatchNode (location: (1,0)-(4,3))
            ├── predicate:
            │   @ ConstantReadNode (location: (1,5)-(1,10))
            │   └── name: :Array
            ├── conditions: (length: 1)
            │   └── @ InNode (location: (2,0)-(3,4))
            │       ├── pattern:
            │       │   @ ConstantReadNode (location: (2,3)-(2,8))
            │       │   └── name: :Class
            │       ├── statements:
            │       │   @ StatementsNode (location: (3,2)-(3,4))
            │       │   └── body: (length: 1)
            │       │       └── @ SymbolNode (location: (3,2)-(3,4))
            │       │           ├── flags: forced_us_ascii_encoding
            │       │           ├── opening_loc: (3,2)-(3,3) = ":"
            │       │           ├── value_loc: (3,3)-(3,4) = "b"
            │       │           ├── closing_loc: ∅
            │       │           └── unescaped: "b"
            │       ├── in_loc: (2,0)-(2,2) = "in"
            │       └── then_loc: ∅
            ├── consequent: ∅
            ├── case_keyword_loc: (1,0)-(1,4) = "case"
            └── end_keyword_loc: (4,0)-(4,3) = "end"