问题：
sudo pip3 install --upgrade
报错
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/pip/_vendor/__init__.py", line 33, in vendored
__import__(vendored_name, globals(), locals(), level=0)
ImportError: No module named 'pip._vendor.pkg_resources'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/bin/pip3", line 9, in
from pip import main
File "/usr/lib/python3/dist-packages/pip/__init__.py", line 13, in
from pip.exceptions import InstallationError, CommandError, PipError
File "/usr/lib/python3/dist-packages/pip/exceptions.py", line 6, in
from pip._vendor.six import iteritems
File "/usr/lib/python3/dist-packages/pip/_vendor/__init__.py", line 75, in
vendored("pkg_resources")
File "/usr/lib/python3/dist-packages/pip/_vendor/__init__.py", line 36, in vendored
__import__(modulename, globals(), locals(), level=0)
File "", line 969, in _find_and_load
File "", line 958, in _find_and_load_unlocked
File "", line 664, in _load_unlocked
File "", line 634, in _load_backward_compatible
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2927, in
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2913, in _call_aside
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2952, in _initialize_master_working_set
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 956, in subscribe
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2952, in
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2515, in activate
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2097, in declare_namespace
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2047, in _handle_ns
File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2066, in _rebuild_mod_path
AttributeError: '_NamespacePath' object has no attribute 'sort'
解决方案：
安装setuptools模块：https://pypi.python.org/pypi/setuptools#files
下载setuptools-36.5.0.zip解压，命令窗口进入到文件夹然后
python setup.py install
easy_install pip
