python爬取有道翻译出错 {‘errorcode’:50}

import urllib.request
import urllib.parse


url = "http://fanyi.youdao.com/translate?smartresult=dict&smartresult=rule"
key=input("请输入需要翻译的文字:")
formdata ={
    "i": key,
    "from": "AUTO",
    "to": "AUTO",
    "smartresult": "dict",
    "client": "fanyideskweb",
    "salt": "1537698317221",
    "sign": "b569c8bf54bf1b0d71725726e7c1a5",
    "doctype": "json",
    "version": "2.1",
    "keyfrom": "fanyi.web",
    "action": "FY_BY_REALTIME",
    "typoResult": "false"
    }
headers={ "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36"}
data = urllib.parse.urlencode(formdata).encode(encoding='gbk')

request = urllib.request.Request(url,data=data, headers = headers)

repost = urllib.request.urlopen(request)

html=repost.read().decode("utf-8")
print(html)

将在审查元素中获得的url中translate后面的_o去掉，错误就消失了，可以正常爬取。

data除了doctype键和i键不能去掉，其余的即使删除了也能正常运行翻译。[此行待验证]