sudo easy_install pip failed on Mac

1. Errorsetuptools-33.1.1     setuptools-33.1.1.zip➜  install sudo easy_install pipPassword:Traceback (most recent call last):  File "/usr/local/bin/easy_install", line 11, in <module>    load_entry_point('setuptools==33.1.1', 'console_scripts', 'easy_install')()  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 565, in load_entry_point    return get_distribution(dist).load_entry_point(group, name)  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 2697, in load_entry_point    return ep.load()  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 2370, in load    return self.resolve()  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 2376, in resolve    module = __import__(self.module_name, fromlist=['__name__'], level=0)  File "build/bdist.macosx-10.12-intel/egg/setuptools/__init__.py", line 10, in <module>  File "build/bdist.macosx-10.12-intel/egg/setuptools/extern/__init__.py", line 1, in <module>ImportError: No module named extern2. Solutiondownload extern from https://pypi.python.org/pypi/extern/0.1.0run command : tarzxf extern-0.1.0.tar.gz && python setup.py install