python 链接mysql 事务

import  mysql.connector

try:
    con = mysql.connector.connect(
        host="localhost", port="3306",
        user="root", password="",
        database="demo"
    )
    con.start_transaction()
    cursor = con.cursor()
    sql = " insert into t_emp(empno, ename, job, mgr,hiredate,sal,comm,deptno)" 
           "values(%s,%s,%s,%s,%s,%s,%s,%s) "
    cursor.execute(sql,(9600,"赵娜","SALESMAN",None,'1985-12-1',2500,None,10))
    con.commit()
except Exception as e:
    if 'con' in dir():
        con.rollback()
    print(e)
finally:
    if 'con' in dir():
        con.close()