ReadTimeoutError: HTTPSConnectionPool(host='files.pythonhosted.org', port=443): Read timed out.

pip --default-timeout=1000 install requests（包名）

ERROR: Exception:
Traceback (most recent call last):
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/urllib3/contrib/pyopenssl.py", line 304, in recv_into
    return self.connection.recv_into(*args, **kwargs)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/OpenSSL/SSL.py", line 1822, in recv_into
    self._raise_ssl_error(self._ssl, result)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/OpenSSL/SSL.py", line 1622, in _raise_ssl_error
    raise WantReadError()
OpenSSL.SSL.WantReadError
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/urllib3/contrib/pyopenssl.py", line 304, in recv_into
    return self.connection.recv_into(*args, **kwargs)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/OpenSSL/SSL.py", line 1822, in recv_into
    self._raise_ssl_error(self._ssl, result)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/OpenSSL/SSL.py", line 1622, in _raise_ssl_error
    raise WantReadError()
OpenSSL.SSL.WantReadError
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/urllib3/response.py", line 397, in _error_catcher
    yield
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/urllib3/response.py", line 479, in read
    data = self._fp.read(amt)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/cachecontrol/filewrapper.py", line 62, in read
    data = self.__fp.read(amt)
  File "/home/zhanshen/anaconda3/lib/python3.7/http/client.py", line 457, in read
    n = self.readinto(b)
  File "/home/zhanshen/anaconda3/lib/python3.7/http/client.py", line 501, in readinto
    n = self.fp.readinto(b)
  File "/home/zhanshen/anaconda3/lib/python3.7/socket.py", line 589, in readinto
    return self._sock.recv_into(b)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/urllib3/contrib/pyopenssl.py", line 319, in recv_into
    return self.recv_into(*args, **kwargs)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/urllib3/contrib/pyopenssl.py", line 317, in recv_into
    raise timeout('The read operation timed out')
socket.timeout: The read operation timed out
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/cli/base_command.py", line 188, in main
    status = self.run(options, args)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/commands/install.py", line 345, in run
    resolver.resolve(requirement_set)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/legacy_resolve.py", line 196, in resolve
    self._resolve_one(requirement_set, req)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/legacy_resolve.py", line 359, in _resolve_one
    abstract_dist = self._get_abstract_dist_for(req_to_install)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/legacy_resolve.py", line 307, in _get_abstract_dist_for
    self.require_hashes
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/operations/prepare.py", line 199, in prepare_linked_requirement
    progress_bar=self.progress_bar
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/download.py", line 1064, in unpack_url
    progress_bar=progress_bar
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/download.py", line 924, in unpack_http_url
    progress_bar)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/download.py", line 1152, in _download_http_url
    _download_url(resp, link, content_file, hashes, progress_bar)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/download.py", line 861, in _download_url
    hashes.check_against_chunks(downloaded_chunks)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/utils/hashes.py", line 75, in check_against_chunks
    for chunk in chunks:
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/download.py", line 829, in written_chunks
    for chunk in chunks:
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/utils/ui.py", line 156, in iter
    for x in it:
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_internal/download.py", line 818, in resp_read
    decode_content=False):
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/urllib3/response.py", line 531, in stream
    data = self.read(amt=amt, decode_content=decode_content)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/urllib3/response.py", line 496, in read
    raise IncompleteRead(self._fp_bytes_read, self.length_remaining)
  File "/home/zhanshen/anaconda3/lib/python3.7/contextlib.py", line 130, in __exit__
    self.gen.throw(type, value, traceback)
  File "/home/zhanshen/anaconda3/lib/python3.7/site-packages/pip/_vendor/urllib3/response.py", line 402, in _error_catcher
    raise ReadTimeoutError(self._pool, None, 'Read timed out.')
pip._vendor.urllib3.exceptions.ReadTimeoutError: HTTPSConnectionPool(host='files.pythonhosted.org', port=443): Read timed out.