如何优雅地中断urllib2下载？

import urllib2

# 假设这是一个全局变量，当它被设置为True时，我们将中断下载
stop_download = False

response = urllib2.urlopen('http://example.com/large-file.zip')
file = open('large-file.zip', 'wb')

while True:
    chunk = response.read(1024)
    if not chunk or stop_download:
        break
    file.write(chunk)

file.close()
response.close()