item-0 at level 0: GroupLabel.UNSPECIFIED: group _root_
  item-1 at level 1: DocItemLabel.TITLE: Example Document
    item-2 at level 2: DocItemLabel.SECTION_HEADER: Introduction
      item-3 at level 3: DocItemLabel.PARAGRAPH: This is the first paragraph of the introduction.
    item-4 at level 2: DocItemLabel.SECTION_HEADER: Background
      item-5 at level 3: DocItemLabel.PARAGRAPH: Some background information here.
      item-6 at level 3: GroupLabel.LIST: group list
        item-7 at level 4: DocItemLabel.LIST_ITEM: First item in unordered list
          item-8 at level 5: GroupLabel.LIST: group list
            item-9 at level 6: DocItemLabel.LIST_ITEM: Nested item 1
            item-10 at level 6: DocItemLabel.LIST_ITEM: Nested item 2
        item-11 at level 4: DocItemLabel.LIST_ITEM: Second item in unordered list
      item-12 at level 3: GroupLabel.ORDERED_LIST: group ordered list
        item-13 at level 4: DocItemLabel.LIST_ITEM: First item in ordered list
          item-14 at level 5: GroupLabel.ORDERED_LIST: group ordered list
            item-15 at level 6: DocItemLabel.LIST_ITEM: Nested ordered item 1
            item-16 at level 6: DocItemLabel.LIST_ITEM: Nested ordered item 2
        item-17 at level 4: DocItemLabel.LIST_ITEM: Second item in ordered list
    item-18 at level 2: DocItemLabel.SECTION_HEADER: Data Table
      item-19 at level 3: DocItemLabel.TABLE with [4x3]