从终端运行pip install matplotlib或pip3 install matplotlib时，出现以下错误。有人可以告诉我为什么会这样吗？我使用的是Ubuntu 16.04。预先感谢。
Collecting matplotlib
Exception:
Traceback (most recent call last):
File "/home/surya/.local/lib/python3.5/site-packages/pip/basecommand.py", line 215, in main
status = self.run(options, args)
File "/home/surya/.local/lib/python3.5/site-packages/pip/commands/install.py", line 335, in run
wb.build(autobuilding=True)
File "/home/surya/.local/lib/python3.5/site-packages/pip/wheel.py", line 749, in build
self.requirement_set.prepare_files(self.finder)
File "/home/surya/.local/lib/python3.5/site-packages/pip/req/req_set.py", line 380, in prepare_files
ignore_dependencies=self.ignore_dependencies))
File "/home/surya/.local/lib/python3.5/site-packages/pip/req/req_set.py", line 554, in _prepare_file
require_hashes
File "/home/surya/.local/lib/python3.5/site-packages/pip/req/req_install.py", line 278, in populate_link
self.link = finder.find_requirement(self, upgrade)
File "/home/surya/.local/lib/python3.5/site-packages/pip/index.py", line 465, in find_requirement
all_candidates = self.find_all_candidates(req.name)
File "/home/surya/.local/lib/python3.5/site-packages/pip/index.py", line 423, in find_all_candidates
for page in self._get_pages(url_locations, project_name):
File "/home/surya/.local/lib/python3.5/site-packages/pip/index.py", line 568, in _get_pages
page = self._get_page(location)
File "/home/surya/.local/lib/python3.5/site-packages/pip/index.py", line 683, in _get_page
return HTMLPage.get_page(link, session=self.session)
File "/home/surya/.local/lib/python3.5/site-packages/pip/index.py", line 792, in get_page
"Cache-Control": "max-age=600",
File "/home/surya/.local/lib/python3.5/site-packages/pip/_vendor/requests/sessions.py", line 488, in get
return self.request('GET', url, **kwargs)
File "/home/surya/.local/lib/python3.5/site-packages/pip/download.py", line 386, in request
return super(PipSession, self).request(method, url, *args, **kwargs)
File "/home/surya/.local/lib/python3.5/site-packages/pip/_vendor/requests/sessions.py", line 475, in request
resp = self.send(prep, **send_kwargs)
File "/home/surya/.local/lib/python3.5/site-packages/pip/_vendor/requests/sessions.py", line 596, in send
r = adapter.send(request, **kwargs)
File "/home/surya/.local/lib/python3.5/site-packages/pip/_vendor/cachecontrol/adapter.py", line 47, in send
resp = super(CacheControlAdapter, self).send(request, **kw)
File "/home/surya/.local/lib/python3.5/site-packages/pip/_vendor/requests/adapters.py", line 390, in send
conn = self.get_connection(request.url, proxies)
File "/home/surya/.local/lib/python3.5/site-packages/pip/_vendor/requests/adapters.py", line 290, in get_connection
proxy_manager = self.proxy_manager_for(proxy)
File "/home/surya/.local/lib/python3.5/site-packages/pip/_vendor/requests/adapters.py", line 184, in proxy_manager_for
**proxy_kwargs
File "/home/surya/.local/lib/python3.5/site-packages/pip/_vendor/requests/adapters.py", line 43, in SOCKSProxyManager
raise InvalidSchema("Missing dependencies for SOCKS support.")
pip._vendor.requests.exceptions.InvalidSchema: Missing dependencies for SOCKS support.