错误代码：
Exception:
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/pip/req/req_install.py", line , in check_if_exists
self.satisfied_by = pkg_resources.get_distribution(str(no_marker))
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line , in get_distribution
dist = get_provider(dist)
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line , in get_provider
return working_set.find(moduleOrReq) or require(str(moduleOrReq))[]
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line , in find
raise VersionConflict(dist, req)
pkg_resources.VersionConflict: (cryptography 1.2. (/usr/lib/python3/dist-packages), Requirement.parse('cryptography>=1.3')) During handling of the above exception, another exception occurred: Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/pip/basecommand.py", line , in main
status = self.run(options, args)
File "/usr/lib/python3/dist-packages/pip/commands/install.py", line , in run
requirement_set.prepare_files(finder)
File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line , in prepare_files
ignore_dependencies=self.ignore_dependencies))
File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line , in _prepare_file
req_to_install, finder)
File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line , in _check_skip_installed
req_to_install.check_if_exists()
File "/usr/lib/python3/dist-packages/pip/req/req_install.py", line , in check_if_exists
self.req.project_name
AttributeError: 'Requirement' object has no attribute 'project_name'
解决方法：安装全所需库文件即可：
sudo apt-get install build-essential
sudo apt-get install python3-dev
sudo apt-get install libxml2-de;
sudo apt-get install libxslt1-dev
sudo apt-get install libssl-dev
apt-get install -y libffi-dev
pip3 install Twisted
pip3 install w3lib
pip3 install lxm