python连接mysql数据库报错__init__() takes 1 positional argument but 5 were given

python连接mysql数据库报错
init() takes 1 positional argument but 5 were given
这是原先的代码

import pymysql

dbhost='localhost'
dbuser='root'
dbpass='root'
dbname='dbtest'

try:
    db=pymysql.connect(dbhost,dbuser,dbpass,dbname)
    print("数据库连接成功")
except pymysql.Error as e:
    print("数据库连接失败："+str(e))

错误原因未明
把连接语句修改成如下就好了

db=pymysql.connect(host=dbhost,user=dbuser,password=dbpass,database=dbname)