@ ProgramNode (location: (1,0)-(7,2))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(7,2))
    └── body: (length: 1)
        └── @ ArrayNode (location: (1,0)-(7,2))
            ├── flags: ∅
            ├── elements: (length: 2)
            │   ├── @ InterpolatedStringNode (location: (1,1)-(1,4))
            │   │   ├── flags: ∅
            │   │   ├── opening_loc: (1,1)-(1,4) = "<<A"
            │   │   ├── parts: (length: 3)
            │   │   │   ├── @ EmbeddedStatementsNode (location: (2,0)-(2,6))
            │   │   │   │   ├── opening_loc: (2,0)-(2,2) = "\#{"
            │   │   │   │   ├── statements:
            │   │   │   │   │   @ StatementsNode (location: (2,2)-(2,5))
            │   │   │   │   │   └── body: (length: 1)
            │   │   │   │   │       └── @ StringNode (location: (2,2)-(2,5))
            │   │   │   │   │           ├── flags: ∅
            │   │   │   │   │           ├── opening_loc: (2,2)-(2,5) = "<<B"
            │   │   │   │   │           ├── content_loc: (3,0)-(4,0) = "b\n"
            │   │   │   │   │           ├── closing_loc: (4,0)-(5,0) = "B\n"
            │   │   │   │   │           └── unescaped: "b\n"
            │   │   │   │   └── closing_loc: (2,5)-(2,6) = "}"
            │   │   │   ├── @ StringNode (location: (2,6)-(3,0))
            │   │   │   │   ├── flags: frozen
            │   │   │   │   ├── opening_loc: ∅
            │   │   │   │   ├── content_loc: (2,6)-(3,0) = "\n"
            │   │   │   │   ├── closing_loc: ∅
            │   │   │   │   └── unescaped: "\n"
            │   │   │   └── @ StringNode (location: (5,0)-(6,0))
            │   │   │       ├── flags: frozen
            │   │   │       ├── opening_loc: ∅
            │   │   │       ├── content_loc: (5,0)-(6,0) = "a\n"
            │   │   │       ├── closing_loc: ∅
            │   │   │       └── unescaped: "a\n"
            │   │   └── closing_loc: (6,0)-(7,0) = "A\n"
            │   └── @ IntegerNode (location: (7,0)-(7,1))
            │       ├── flags: decimal
            │       └── value: 0
            ├── opening_loc: (1,0)-(1,1) = "["
            └── closing_loc: (7,1)-(7,2) = "]"