{
  "tag": "simple_dag",
  "tasks": {
    "task_a": {
      "job": {
        "command": [ "/bin/echo", "I", "run", "first" ]
      },
      "children": [ "task_b" ]
    },
    "task_b": {
      "job": {
        "command": [ "/bin/echo", "I", "run", "second" ]
      }
    }
  }
}