python 切换root 执行命令的方法

def create_user(root_pwd,username,password):  import paramiko  result = []  ssh = paramiko.SSHClient()  #把要连接的机器添加到known_hosts文件中  ssh.load_system_host_keys()  ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())  ssh.connect(       hostname = settings.HOST,       port = settings.PORT,       username = settings.USERNAME,       password = settings.PASSWORD,       timeout = 60,     )  sc = ssh.invoke_shell()   def exe_cmd(cmd,t=0.1):    sc.send(cmd)    sc.send("/n")    time.sleep(t)    resp = sc.recv(9999).decode("utf8")    #print "cmd='%s',echo='%s'/n"%(cmd,resp)    return resp    #切换root账号  resp = exe_cmd("su root",t=1)  if resp.endswith(u"密码："):    resp = exe_cmd(root_pwd)    #创建用户  cmd_create_user = "useradd {username} -d /home/{username}".format(    username = username,  )  exe_cmd(cmd_create_user)   #修改密码  cmd_change_user_pwd = """echo "{password}" | passwd --stdin {username}""".format(    username = username,    password = password,  )  exe_cmd(cmd_change_user_pwd)