在阅读一些CTF写作时,我遇到了这个脚本

#!/usr/bin/env python
import struct
import Image
import dpkt

INIT_X,INIT_Y = 100,400

def print_map(pcap,device):
    picture = Image.new("RGB",(1200,500),"white")
    pixels = picture.load() 

    x,y = INIT_X,INIT_Y

    for ts,buf in pcap:
        device_id,= struct.unpack("b",buf[0x0B])

        if device_id != device:
            continue

        data = struct.unpack("bbbb",buf[-4:])

        status = data[0]
        x = x + data[1]
        y = y + data[2]

        if (status == 1):
            for i in range(-5,5):
                for j in range(-5,5):
                    pixels[x + i,y + j] = (0,0)
        else:
            pixels[x,y] = (255,0)
    picture.save("riverside-map.png","PNG")

if __name__ == "__main__":

    f = open("usb.pcap","rb")
    pcap = dpkt.pcap.Reader(f)
    print_map(pcap,5)
    f.close()

当我在我的usb.pcap上运行它时,我收到此错误：

 Traceback (most recent call last):
      File "test.py",line 39,in