Http yaml error

# yaml file demo for http
workflow:
name: "Http"

# Define the tasks within the workflow
tasks:
- name: task
task_type: Http
url: https://httpbin.org/get
http_method: GET
http_params:
- prop: a
httpParametersType: PARAMETER
value: "1"
- prop: b
httpParametersType: PARAMETER
value: "2"
- prop: Content-Type
httpParametersType: header
value: test
http_check_condition: STATUS_CODE_CUSTOM
condition: "404"
type: Http
task_params: {}

raise PyDSParamException(
"Parameter `params` must be a dict, but get %s", type(params)
)
pydolphinscheduler.exceptions.PyDSParamException: ('Parameter `params` must be a dict, but get %s', )