python – 使用pip的问题,(异常[…] findall()只需要2个参数(给

每当我尝试使用pip时,我都会遇到此异常(以Scrapy为例)：

C:Python27Scriptspip-script.py run on 01/16/14 16:26:32
Requirement already satisfied (use --upgrade to upgrade): Scrapy in c:python27libsite-packagesscrapy-0.20.2-py2.7.egg
Requirement already satisfied (use --upgrade to upgrade): Twisted>=10.0.0 in c:python27libsite-packages (from Scrapy)
Downloading/unpacking w3lib>=1.2 (from Scrapy)
  Getting page https://pypi.python.org/simple/w3lib/
  URLs to search for versions for w3lib>=1.2 (from Scrapy):
  * https://pypi.python.org/simple/w3lib/
  Analyzing links from page https://pypi.python.org/simple/w3lib/
Cleaning up...
  Removing temporary dir c:userstobiasappdatalocaltemppip_build_Tobias...
Exception:
Traceback (most recent call last):
  File "c:python27libsite-packagespipbasecommand.py",line 122,in main
    status = self.run(options,args)
  File "c:python27libsite-packagespipcommandsinstall.py",line 270,in run
    requirement_set.prepare_files(finder,force_root_egg_info=self.bundle,bundle=self.bundle)
  File "c:python27libsite-packagespipreq.py",line 1157,in prepare_files
    url = finder.find_requirement(req_to_install,upgrade=self.upgrade)
  File "c:python27libsite-packagespipindex.py",line 264,in find_requirement
    page_versions.extend(self._package_versions(page.links,req.name.lower()))
  File "c:python27libsite-packagespipindex.py",line 440,in _package_versions
    for link in self._sort_links(links):
  File "c:python27libsite-packagespipindex.py",line 430,in _sort_links
    for link in links:
  File "c:python27libsite-packagespipindex.py",line 772,in links
    for anchor in self.parsed.findall(".//a"):
TypeError: findall() takes exactly 2 arguments (3 given)

我正在使用Windows 7 32位,Python 2.7