@ DocumentNode (location: (1:0)-(1:16))
└── children: (1 item)
    └── @ HTMLElementNode (location: (1:0)-(1:16))
        ├── open_tag:
        │   └── @ HTMLOpenTagNode (location: (1:0)-(1:16))
        │       ├── tag_opening: "<" (location: (1:0)-(1:1))
        │       ├── tag_name: "input" (location: (1:1)-(1:6))
        │       ├── tag_closing: ">" (location: (1:15)-(1:16))
        │       ├── children: (1 item)
        │       │   └── @ HTMLAttributeNode (location: (1:7)-(1:15))
        │       │       ├── name:
        │       │       │   └── @ HTMLAttributeNameNode (location: (1:7)-(1:15))
        │       │       │       └── name: "required" (location: (1:7)-(1:15))
        │       │       │
        │       │       ├── equals: ∅
        │       │       └── value: ∅
        │       │
        │       └── is_void: false
        │
        ├── tag_name: "input" (location: (1:1)-(1:6))
        ├── body: []
        ├── close_tag: ∅
        └── is_void: true