@ ProgramNode (location: (1,0)-(3,4))
├── flags: ∅
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(3,4))
    ├── flags: ∅
    └── body: (length: 2)
        ├── @ InterpolatedStringNode (location: (1,0)-(2,2))
        │   ├── flags: newline
        │   ├── opening_loc: (1,0)-(1,1) = "\""
        │   ├── parts: (length: 2)
        │   │   ├── @ StringNode (location: (1,1)-(1,4))
        │   │   │   ├── flags: static_literal, frozen
        │   │   │   ├── opening_loc: ∅
        │   │   │   ├── content_loc: (1,1)-(1,4) = "a\\n"
        │   │   │   ├── closing_loc: ∅
        │   │   │   └── unescaped: "a\n"
        │   │   └── @ EmbeddedStatementsNode (location: (1,4)-(2,1))
        │   │       ├── flags: ∅
        │   │       ├── opening_loc: (1,4)-(1,6) = "\#{"
        │   │       ├── statements: ∅
        │   │       └── closing_loc: (2,0)-(2,1) = "}"
        │   └── closing_loc: (2,1)-(2,2) = "\""
        └── @ TrueNode (location: (3,0)-(3,4))
            └── flags: newline, static_literal
