YUM 오류 질문드려요..

안녕하세요..
뭔가 설치를 마구하다보니.갑짜기.. yum 이 오류나서 그러는데.. 어떻게 해결하나요..

재설치하는방법이라던가..아무튼 알려주심감사하겠습니다.

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Plugin "presto" can't be imported
Plugin "refresh-packagekit" can't be imported
Loaded plugins: langpacks
Traceback (most recent call last):
File "/bin/yum", line 29, in
yummain.user_main(sys.argv[1:], exit_code=True)
File "/usr/share/yum-cli/yummain.py", line 319, in user_main
errcode = main(args)
File "/usr/share/yum-cli/yummain.py", line 144, in main
result, resultmsgs = base.doCommands()
File "/usr/share/yum-cli/cli.py", line 485, in doCommands
return self.yum_cli_commands[self.basecmd].doCommand(self, self.basecmd, self.extcmds)
File "/usr/share/yum-cli/yumcommands.py", line 405, in doCommand
return base.updatePkgs(extcmds, update_to=(basecmd == 'update-to'))
File "/usr/share/yum-cli/cli.py", line 899, in updatePkgs
self.update()
File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 4697, in update
updates = self.up.getUpdatesTuples()
File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1032, in
up = property(fget=lambda self: self._getUpdates(),
File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 839, in _getUpdates
self._up = rpmUtils.updates.Updates(self.rpmdb.simplePkgList(), self.pkgSack.simplePkgList())
File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1013, in
pkgSack = property(fget=lambda self: self._getSacks(),
File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 779, in _getSacks
self.repos.populateSack(which=repos)
File "/usr/lib/python2.7/site-packages/yum/repos.py", line 309, in populateSack
self.doSetup()
File "/usr/lib/python2.7/site-packages/yum/repos.py", line 134, in doSetup
self.retrieveAllMD()
File "/usr/lib/python2.7/site-packages/yum/repos.py", line 84, in retrieveAllMD
dl = repo._async and repo._commonLoadRepoXML(repo)
File "/usr/lib/python2.7/site-packages/yum/yumRepo.py", line 1416, in _commonLoadRepoXML
self._repoXML = self._parseRepoXML(result)
File "/usr/lib/python2.7/site-packages/yum/yumRepo.py", line 1212, in _parseRepoXML
return repoMDObject.RepoMD(self.id, local)
File "/usr/lib/python2.7/site-packages/yum/repoMDObject.py", line 124, in __init__
self.parse(srcfile)
File "/usr/lib/python2.7/site-packages/yum/repoMDObject.py", line 140, in parse
parser = iterparse(infile)
File "/usr/lib/python2.7/site-packages/yum/misc.py", line 1218, in cElementTree_iterparse
return __cached_cElementTree.iterparse(filename)
File "", line 78, in __init__
RuntimeError: cannot load dispatch table from pyexpat
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