python的ssh报错‘No handlers could be found for logger "paramiko.transport"’

ssh函数：
def ssh_cmd(ip,port,user,passwd,cmd):
    out = None
    ssh = None
    try:
        ssh = paramiko.SSHClient() 
        ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        ssh.connect(ip,port,user,passwd,timeout=5) 
        stdin, stdout, stderr = ssh.exec_command(cmd)
        out = stdout.readlines()
        print out
#         log('\n'.join(out))
    except Exception, e:
        error('ssh_cmd error: ' %e) 
    finally:
        if ssh:
            ssh.close()
    return out

执行：ssh_cmd(proxyIp,proxyPort,user,passwd,cmd)-------正确理解：proxyPort应该为远程登陆机器proxyIP的ssh端口，默认是22，不是代理服务的端口（错误理解：其中proxyIP是代理服务器的IP地址，proxyPort为代理服务器的端口）
提示：
No handlers could be found for logger "paramiko.transport"
Traceback (most recent call last):
  File "http_request.py", line 135, in
    main()
  File "http_request.py", line 127, in main
    get_squid_log("192.168.10.74",80,"root","redhat")
  File "http_request.py", line 116, in get_squid_log
    tmp=ssh_cmd(proxyIp,proxyPort,user,passwd,cmd)
  File "http_request.py", line 33, in ssh_cmd
    error('ssh_cmd error: ' %e) 
NameError: global name 'error' is not defined

原因：
ssh_cmd(ip,port,user,passwd,cmd)
我端口写错了，写成80了,默认应该为22
再次执行程序，不再报错，成功了！




扩充：
修改ssh的端口号：vim /etc/ssh/sshd_config
使修改生效：/etc/init.d/sshd restart