我正在尝试使用本教程在我的ec2示例上设置hadoop。当我遇到以下错误时，我正在尝试设置ambari服务器：

[root@ip-xxx-xxx-xxx-xxx ec2-user]# ambari-server setup
Using python  /usr/bin/python2.6
Setup ambari-server
Checking SELinux...
WARNING: Could not run /usr/sbin/sestatus: OK
Ambari-server daemon is configured to run under user 'root'. Change this setting [y/n] (n)?
Adjusting ambari-server permissions and ownership...
Checking iptables...
Checking JDK...
JCE Policy archive already exists, using /var/lib/ambari-server/resources/jce_policy-6.zip
Completing setup...
Traceback (most recent call last):
  File "/usr/sbin/ambari-server.py", line 4236, in <module>
    main()
  File "/usr/sbin/ambari-server.py", line 4055, in main
    setup(options)
  File "/usr/sbin/ambari-server.py", line 2089, in setup
    retcode = configure_os_settings()
  File "/usr/sbin/ambari-server.py", line 1909, in configure_os_settings
    os_name = os_info[0].lower()
AttributeError: 'NoneType' object has no attribute 'lower'

我真的不知道这是怎么发生的，也不知道该怎么做来解决这个问题。有人知道我做错了什么吗？
编辑：我在网站上查看了代码，发现：

os_info = platform.linux_distribution(
    None, None, None, ['SuSE', 'redhat' ], 0
  )
  os_name = os_info[0].lower()

看来 platform.linux_distribution 是用它的参数创建一个数组并对其执行其他操作。我在文件中找不到函数的实现，并且有几个文件在同一个目录中，仍然不确定该怎么办。