win7升级PIP9.0.1出错

wunaicj

c:\pip-9.0.1>python setup.py install
Traceback (most recent call last):
   File "setup.py", line 92, in <module>
     cmdclass={'test': PyTest},
   File "C:\Python27\lib\distutils\core.py", line 111, in setup
     _setup_distribution = dist = klass(attrs)
   File "C:\Python27\lib\site-packages\setuptools\dist.py", line 225, in __init__
     _Distribution.__init__(self,attrs)
   File "C:\Python27\lib\distutils\dist.py", line 287, in __init__
     self.finalize_options()
   File "C:\Python27\lib\site-packages\setuptools\dist.py", line 258, in finalize_options
     ep.load()(self, ep.name, value)
   File "C:\Python27\lib\site-packages\pkg_resources\__init__.py", line 2287, in load
     return self.resolve()
   File "C:\Python27\lib\site-packages\pkg_resources\__init__.py", line 2297, in resolve
     raise ImportError(str(exc))
ImportError: 'module' object has no attribute 'check_specifier'

哪位大神给指点一下，多谢了。