pipenv Error

jordi@i-ching:/DATA/Python/requests$ pipenv
Traceback (most recent call last):
  File "/usr/local/bin/pipenv", line 9, in <module>
    load_entry_point('pipenv==9.0.1', 'console_scripts', 'pipenv')()
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 356, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2476, in load_entry_point
    return ep.load()
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2190, in load
    ['__name__'])
  File "/usr/local/lib/python2.7/dist-packages/pipenv/__init__.py", line 17, in <module>
    from .cli import cli
  File "/usr/local/lib/python2.7/dist-packages/pipenv/cli.py", line 27, in <module>
    import flake8.main.cli
  File "/usr/local/lib/python2.7/dist-packages/flake8/main/cli.py", line 2, in <module>
    from flake8.main import application
  File "/usr/local/lib/python2.7/dist-packages/flake8/main/application.py", line 14, in <module>
    from flake8.main import options
  File "/usr/local/lib/python2.7/dist-packages/flake8/main/options.py", line 3, in <module>
    from flake8.main import debug
  File "/usr/local/lib/python2.7/dist-packages/flake8/main/debug.py", line 7, in <module>
    import setuptools
  File "/usr/local/lib/python2.7/dist-packages/setuptools/__init__.py", line 10, in <module>
    from setuptools.extern.six.moves import filter, map
  File "/usr/local/lib/python2.7/dist-packages/setuptools/extern/__init__.py", line 1, in <module>
    from pkg_resources.extern import VendorImporter
ImportError: No module named extern