问OSError：[Errno 9]错误的文件描述符

EN

import socket, ssl, pprint
import os, time
import threading

def main():
    s2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    ssl_sock = ssl.wrap_socket(s2,
                           server_side = False,
                           ca_certs="CA.crt",
                           cert_reqs=ssl.CERT_REQUIRED)
    s2.connect(('localhost',10024))
    filename = raw_input("What file do you wish to download? -> ")

    if filename != 'q':
        s2.send(filename)

        data = s2.recv(1024)
        if data [:7] == 'fEXISTS':
            fSize = long(data[7:])

            message = raw_input("The file you wish to download is " +str(fSize)+\
                        "bytes, would you like to proceed? (y/n): ")

            if message == 'y':
                s2.send ('OK')
                f = open('new_'+filename, 'wb')
                data = s2.recv(2000000)
                totalRecv = len(data)
                f.write(data)

                while totalRecv < fSize:
                    data = s2.recv(2000000)
                    totalRecv += len(data)
                    f.write(data)
                    progress = ((totalRecv/float(fSize))*100)
                    print ("{0: .2F}".format(progress)+\
                            "% Completed")
        else:
            print ("ERROR: File does not exist!")
    s2.close()

if __name__ == '__main__':
    main()