Python pip pkg_resources.distribution未找到

Question

Pip看到一个版本为1.4.0的包，但随后抱怨我需要>=0.9.34的版本。不是1.4.0 > 0.9.34吗？

root@36e7a0a55174:~/tldr-integration-tests# pip show testtools
---
Name: testtools
Version: 1.4.0
Location: /usr/local/lib/python2.7/dist-packages
Requires: python-mimeparse, unittest2, extras
root@36e7a0a55174:~/tldr-integration-tests# lettuce ./tldr_integration_tests
Traceback (most recent call last):
  File "/usr/local/bin/lettuce", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2707, in <module>
    working_set.require(__requires__)
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 686, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 584, in resolve
    raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: testtools>=0.9.34
root@36e7a0a55174:~/tldr-integration-tests# pip --version
pip 1.5.6 from /usr/local/lib/python2.7/dist-packages/pip-1.5.6-py2.7.egg (python 2.7)