:stderr: Traceback (most recent call last):

 "/usr/bin/pip", line 9, in <module>
load_entry_point('pip==1.5.4', 'console_scripts', 'pip')()

 "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 351, in load_entry_point
return get_distribution(dist).load_entry_point(group, name)

 "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2363, in load_entry_point
return ep.load()

 "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2088, in load
entry = __import__(self.module_name, globals(),globals(), ['__name__'])

 "/usr/lib/python2.7/dist-packages/pip/__init__.py", line 11, in <module>
from pip.vcs import git, mercurial, subversion, bazaar
# noqa

 "/usr/lib/python2.7/dist-packages/pip/vcs/mercurial.py", line 9, in <module>
from pip.download import path_to_url

 "/usr/lib/python2.7/dist-packages/pip/download.py", line 25, in <module>
from requests.compat import IncompleteReadImportError: cannot import name IncompleteRead
Traceback (most recent call last):

 "[...]/matplotlib/lib/matplotlib/colors.py", line 370, in to_rgba
r, g, b = self.to_rgb(arg)

 "[...]/matplotlib/lib/matplotlib/colors.py", line 328, in to_rgb
'to_rgb: Invalid rgb arg "%s"\n%s' % (str(arg), exc))ValueError: to_rgb: Invalid rgb arg "None"