python怎么使用form-data形式上传文件请求

import requests
import json
from requests_toolbelt.multipart.encoder import MultipartEncoder
 
url='Http://XXX.xxx.xxx.xx:9900/api-marketing-center/poster/save'
 
data={'activityName':'我是个海报2',
        'backgroundPicUrl':'https://xxxxx/default/f865a1aa66adfe50d005bd840e2c3356.jpg',
        'copywriting':'我是个海报  看看我2',
        'endTime':'2021-08-14 16:00:00',
        'startTime':'2021-08-11 16:00:00',
        'giftPicUrl':'https://xxxxx/file/c363c3173ac7c02393bf60018031073D.PNG',
        'qrCodeUrl':'https://xxxxxx/file/c363c3173ac7c02393bf60018031073d.PNG',
        'posterUrlThumbnail':'文件'
        }
files = {"posterUrlThumbnail": open('C:/Users/Lenovo/Desktop/格式测试/12.PNG', "rb")}
 
headers={'AUTH_MERCHANTS_ID': '76',
'Authorization': 'Bearer ad8cbdf3-c827-470a-aba5-076f0f3a9628'}  
 
r=requests.post(url=url,params=data, headers=headers,files=files)
 
print(r.json())
 
#{'code': 0, 'msg': '操作成功', 'data': None}