title: Error when trying to use pip
body: <p>I have the same error as this post:
  <a href="https://stackoverflow.com/questions/37495375/python-pip-install-throws-typeerror-unsupported-operand-types-for-retry">Python PIP Install throws TypeError: unsupported operand type(s) for -=: &#39;Retry&#39; and &#39;int&#39;</a></p>
  
  <p>I get the same error whatever I try to install using pip.
  system info: Linux version 4.4.0-38-generic (buildd@lgw01-58) (gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.2) ) #57-Ubuntu SMP Tue Sep 6 15:42:33 UTC 2016</p>
  
  <p>If I try to use the solution posted on that question, I get unreachable error:</p>
  
  <pre><code>$ sudo python get-pip.py
  The directory '/home/theoa/.cache/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
  The directory '/home/theoa/.cache/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
  Retrying (Retry(total=4, connect=None, read=None, redirect=None)) after connection broken by 'NewConnectionError('&lt;pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f344927ee50&gt;: Failed to establish a new connection: [Errno 101] Network is unreachable',)': /simple/pip/
  Retrying (Retry(total=3, connect=None, read=None, redirect=None)) after connection broken by 'NewConnectionError('&lt;pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f344ac77a10&gt;: Failed to establish a new connection: [Errno 101] Network is unreachable',)': /simple/pip/
  Retrying (Retry(total=2, connect=None, read=None, redirect=None)) after connection broken by 'NewConnectionError('&lt;pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f344ac77b90&gt;: Failed to establish a new connection: [Errno 101] Network is unreachable',)': /simple/pip/
  Retrying (Retry(total=1, connect=None, read=None, redirect=None)) after connection broken by 'NewConnectionError('&lt;pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f344ac77d10&gt;: Failed to establish a new connection: [Errno 101] Network is unreachable',)': /simple/pip/
  Retrying (Retry(total=0, connect=None, read=None, redirect=None)) after connection broken by 'NewConnectionError('&lt;pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f344ac77e90&gt;: Failed to establish a new connection: [Errno 101] Network is unreachable',)': /simple/pip/
  </code></pre>
  
  <p>I did try to post this in a reply in the original thread but apparently that was wrong thing to do and it got deleted. </p>
  
  <p>Here's the original error, thanks.</p>
  
  <pre><code>Exception:
  Traceback (most recent call last):
    File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 209, in main
      status = self.run(options, args)
    File "/usr/lib/python2.7/dist-packages/pip/commands/install.py", line 317, in run
      requirement_set.prepare_files(finder)
    File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 360, in prepare_files
      ignore_dependencies=self.ignore_dependencies))
    File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 512, in _prepare_file
      finder, self.upgrade, require_hashes)
    File "/usr/lib/python2.7/dist-packages/pip/req/req_install.py", line 273, in populate_link
      self.link = finder.find_requirement(self, upgrade)
    File "/usr/lib/python2.7/dist-packages/pip/index.py", line 442, in find_requirement
      all_candidates = self.find_all_candidates(req.name)
    File "/usr/lib/python2.7/dist-packages/pip/index.py", line 400, in find_all_candidates
      for page in self._get_pages(url_locations, project_name):
    File "/usr/lib/python2.7/dist-packages/pip/index.py", line 545, in _get_pages
      page = self._get_page(location)
    File "/usr/lib/python2.7/dist-packages/pip/index.py", line 648, in _get_page
      return HTMLPage.get_page(link, session=self.session)
    File "/usr/lib/python2.7/dist-packages/pip/index.py", line 757, in get_page
      "Cache-Control": "max-age=600",
    File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 480, in get
      return self.request('GET', url, **kwargs)
    File "/usr/lib/python2.7/dist-packages/pip/download.py", line 378, in request
      return super(PipSession, self).request(method, url, *args, **kwargs)
    File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 468, in request
      resp = self.send(prep, **send_kwargs)
    File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 576, in send
      r = adapter.send(request, **kwargs)
    File "/usr/share/python-wheels/CacheControl-0.11.5-py2.py3-none-any.whl/cachecontrol/adapter.py", line 46, in send
      resp = super(CacheControlAdapter, self).send(request, **kw)
    File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/adapters.py", line 376, in send
      timeout=timeout
    File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 610, in urlopen
      _stacktrace=sys.exc_info()[2])
    File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/util/retry.py", line 228, in increment
      total -= 1
  TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'
  </code></pre>