a bytes-like object is required, not 'str'怎么解决？

import socket
import struct
import time
import win32api
TimeServer = '210.72.145.44'
Port = 123
def getTime():
TIME_1970 = 2208988800
client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
data = '\x1b' + 47 * '\0'
client.sendto(data, (TimeServer, Port))
data, address = client.recvfrom(1024)
data_result = struct.unpack('!12I', data)[10]
data_result -= TIME_1970
return data_result
这些代码中在 data = '\x1b' + 47 * '\0'这一行总是报a bytes-like object is required, not 'str'的问题，这个是怎么解决啊，谢谢