Document(Document, 'None', 'None', None)
  DocumentType(DocumentType, root, None, None)
    EntityDecl(EntityDecl, ent, None, None, None, 'attvalue')
  Element(Element, root, root, None, None)
    Attribute(Attribute, attr, attr, None, None, 'attvalue')
      Text(Text, 'attvalue')
