解决No module named yum

yum install bzip2-devel
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:

   No module named yum

Please install a package which provides this module, or
verify that the module is installed correctly.

It's possible that the above module doesn't match the
current version of Python, which is:
2.7.9 (default, Feb 20 2021, 17:56:59) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-18)]
  
If you cannot solve this problem yourself, please go to 
the yum faq at:
  http://yum.baseurl.org/wiki/Faq

yum命令是linux系统里默认的命令，现在不好用是因为python的问题，因为我在机器重新安装了python的新版本，修改如下：

vim /usr/bin/yum

#首行修改成（系统python原版本是2.6.6）
#!/usr/bin/python  --> #!/usr/bin/python2.6.6

保存后就可以使用了