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'

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