document:
  nodes:
    - object: block
      type: code_block
      data:
        syntax: java
      nodes:
        - object: block
          type: code_line
          nodes:
            - object: text
              leaves:
                - text: ''
    - object: block
      type: paragraph
      nodes:
        - object: text
          leaves:
            - text: Hello world
    - object: block
      type: code_block
      data:
        syntax: java
      nodes:
        - object: block
          type: code_line
          nodes:
            - object: text
              leaves:
                - text: Second