tornado information output to the browser

The information is returned to the browser

val_json=json.dumps(dict(responsecode="0",info=back_info),indent=4,default=str)
self.write(val_jso)

{ "info": [ { "vm_state": "active", "project_id": "", "display_name": "test01.xmgl.aaa", "uuid": "", "GROUP_CONCAT(value)": "centos7.4", "created_at": 1545728514000, "launched_on": "", "host_ip": "", "memory_mb": 4096, "device_id": "", "host": "", "size_rootvolume": 20, "GROUP_CONCAT(distinct ip_address)": "", "vip": "", "size_datavolume": 30.0, "task_state": "", "vcpus": 2, "description": "\u8fd0\u8425\u652f\u6491\u90e8" } ], "responsecode": "0" }

The formatted information is returned to the browser

self.set_header("Content-Type","application/json")
val_json=json.dumps(dict(responsecode="0",info=back_info),indent=4,default=str)
self.write(val_jso)

{
    "info": [
        {
            "vm_state": "active", 
            "project_id": "", 
            "display_name": "test01.xmgl.aaa", 
            "uuid": "", 
            "GROUP_CONCAT(value)": "centos7.4", 
            "created_at": 1545728514000, 
            "launched_on": "", 
            "host_ip": "", 
            "memory_mb": 4096, 
            "device_id": "", 
            "host": "", 
            "size_rootvolume": 20, 
            "GROUP_CONCAT(distinct ip_address)": "", 
            "vip": "", 
            "size_datavolume": 30.0, 
            "task_state": "", 
            "vcpus": 2, 
            "description": "\u8fd0\u8425\u652f\u6491\u90e8"
        }
    ], 
    "responsecode": "0"
}