document:
  nodes:
    - object: block
      type: ul_list
      nodes:
        - object: block
          type: list_item
          nodes:
            - object: text
              leaves:
                - text: "1st item"
        - object: block
          type: NOT_AN_ITEM
          nodes:
            - object: text
              leaves:
                - text: "2nd item"
        - object: block
          type: list_item
          nodes:
            - object: text
              leaves:
                - text: "3rd item"