@ ProgramNode (location: (0...29))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...29))
    └── body: (length: 1)
        └── @ CallNode (location: (0...29))
            ├── receiver:
            │   @ CallNode (location: (0...1))
            │   ├── receiver: ∅
            │   ├── call_operator_loc: ∅
            │   ├── message_loc: (0...1) = "h"
            │   ├── opening_loc: ∅
            │   ├── arguments: ∅
            │   ├── closing_loc: ∅
            │   ├── block: ∅
            │   ├── flags: variable_call
            │   └── name: "h"
            ├── call_operator_loc: ∅
            ├── message_loc: (1...4) = "[k]"
            ├── opening_loc: (1...2) = "["
            ├── arguments:
            │   @ ArgumentsNode (location: (2...29))
            │   └── arguments: (length: 2)
            │       ├── @ CallNode (location: (2...3))
            │       │   ├── receiver: ∅
            │       │   ├── call_operator_loc: ∅
            │       │   ├── message_loc: (2...3) = "k"
            │       │   ├── opening_loc: ∅
            │       │   ├── arguments: ∅
            │       │   ├── closing_loc: ∅
            │       │   ├── block: ∅
            │       │   ├── flags: variable_call
            │       │   └── name: "k"
            │       └── @ BeginNode (location: (5...29))
            │           ├── begin_keyword_loc: (5...10) = "begin"
            │           ├── statements:
            │           │   @ StatementsNode (location: (18...20))
            │           │   └── body: (length: 1)
            │           │       └── @ IntegerNode (location: (18...20))
            │           │           └── flags: decimal
            │           ├── rescue_clause: ∅
            │           ├── else_clause: ∅
            │           ├── ensure_clause: ∅
            │           └── end_keyword_loc: (26...29) = "end"
            ├── closing_loc: (3...4) = "]"
            ├── block: ∅
            ├── flags: ∅
            └── name: "[]="
