python3.5 模拟UDP客户端发送数据报文，报错：TypeError: a bytes-like object is required, not 'str'

#!/usr/bin/env python
# -*- coding:utf-8 -*-

import socket

target_host = "127.0.0.1"
target_port = 80

#建立一个socket对象
client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

#发送一些数据
response = client.sendto(("AAABBBCCC"),(target_host,target_port))

print(response)

#接收一些数据
data, addr = client.recvfrom(4096)

print(data)

报错：    response = client.sendto(("AAABBBCCC"),(target_host,target_port))

TypeError: a bytes-like object is required, not 'str'

解决方法：

response = client.sendto(("AAABBBCCC").encode(),(target_host.encode(),target_port))