@ ProgramNode (location: (0...14))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...14))
    └── body: (length: 1)
        └── @ InterpolatedStringNode (location: (0...14))
            ├── opening_loc: (0...1) = "\""
            ├── parts: (length: 5)
            │   ├── @ EmbeddedVariableNode (location: (1...4))
            │   │   ├── operator_loc: (1...2) = "#"
            │   │   └── variable:
            │   │       @ InstanceVariableReadNode (location: (2...4))
            │   │       └── name: :@a
            │   ├── @ StringNode (location: (4...5))
            │   │   ├── opening_loc: ∅
            │   │   ├── content_loc: (4...5) = " "
            │   │   ├── closing_loc: ∅
            │   │   └── unescaped: " "
            │   ├── @ EmbeddedVariableNode (location: (5...9))
            │   │   ├── operator_loc: (5...6) = "#"
            │   │   └── variable:
            │   │       @ ClassVariableReadNode (location: (6...9))
            │   │       └── name: :@@a
            │   ├── @ StringNode (location: (9...10))
            │   │   ├── opening_loc: ∅
            │   │   ├── content_loc: (9...10) = " "
            │   │   ├── closing_loc: ∅
            │   │   └── unescaped: " "
            │   └── @ EmbeddedVariableNode (location: (10...13))
            │       ├── operator_loc: (10...11) = "#"
            │       └── variable:
            │           @ GlobalVariableReadNode (location: (11...13))
            │           └── name: :$a
            └── closing_loc: (13...14) = "\""
