Comment résoudre ReadTimeoutError: HTTPSConnectionPool(host='pypi.python.org', port=443) avec pip?

récemment, j'ai besoin d'installer certains paquets

pip install future
pip install scikit-learn
pip install numpy
pip install scipy

j'ai aussi essayé par writin sudo avant eux, mais il est venu avec les erreurs suivantes dans les lignes rouges:

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 290, 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 1198, in prepare_files
    do_download,
  File "/usr/lib/python2.7/dist-packages/pip/req.py", line 1376, in unpack_url
    self.session,
  File "/usr/lib/python2.7/dist-packages/pip/download.py", line 572, in unpack_http_url
    download_hash = _download_url(resp, link, temp_location)
  File "/usr/lib/python2.7/dist-packages/pip/download.py", line 433, in _download_url
    for chunk in resp_read(4096):
  File "/usr/lib/python2.7/dist-packages/pip/download.py", line 421, in resp_read
    chunk_size, decode_content=False):
  File "/usr/lib/python2.7/dist-packages/urllib3/response.py", line 256, in stream
    data = self.read(amt=amt, decode_content=decode_content)
  File "/usr/lib/python2.7/dist-packages/urllib3/response.py", line 201, in read
    raise ReadTimeoutError(self._pool, None, 'Read timed out.')
ReadTimeoutError: HTTPSConnectionPool(host='pypi.python.org', port=443): Read timed out.

Storing debug log for failure in /root/.pip/pip.log'