ubuntu 下用 pip install 安装 markdown 时出现以下问题怎么解决啊?

[tooweakchen]

Exception:
Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 122, in main
status = self.run(options, args)
File "/usr/lib/python2.7/dist-packages/pip/commands/install.py", line 278, in run
requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle)
File "/usr/lib/python2.7/dist-packages/pip/req.py", line 1259, in prepare_files
)[0]
IndexError: list index out of range

Storing debug log for failure in /home/tooweakchen/.pip/pip.log

[glasslion]

http://stackoverflow.com/questions/23901687/pip-install-broken-pkg-resources-find-distribution-returns-empty-list-in-req-py

https://github.com/pypa/pip/issues/844

May help