pip kann nichts installieren, Fehler: ungültiger Befehl 'egg_info'

Ich habe kürzlich Python von ihrer Website heruntergeladen, zusätzlich zu der Python-Version, die bereits mit Mac OSX geliefert wird. Dies war der Zeitpunkt, an dem ich Probleme mit der Installation von Paketen mit pip hatte.

sudo pip install -vvv pygoogle

Wird Folgendes ausgeben:

The directory '/Users/robot/Library/Caches/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
The directory '/Users/robot/Library/Caches/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Collecting pygoogle
  Getting page https://pypi.python.org/simple/pygoogle/
  Starting new HTTPS connection (1): pypi.python.org
  "GET /simple/pygoogle/ HTTP/1.1" 200 233
  1 location(s) to search for versions of pygoogle:
  * https://pypi.python.org/simple/pygoogle/
  Getting page https://pypi.python.org/simple/pygoogle/
  "GET /simple/pygoogle/ HTTP/1.1" 200 233
  Analyzing links from page https://pypi.python.org/simple/pygoogle/
    Found link https://pypi.python.org/packages/source/p/pygoogle/pygoogle-0.6.tar.gz#md5=f9053f1b7350b899811a7c9226c8a2cb (from https://pypi.python.org/simple/pygoogle/), version: 0.6
    Skipping link http://www.google.com/apis/ (from https://pypi.python.org/simple/pygoogle/); not a file
  "GET /packages/source/p/pygoogle/pygoogle-0.6.tar.gz HTTP/1.1" 200 33672
  Downloading pygoogle-0.6.tar.gz
  Downloading from URL https://pypi.python.org/packages/source/p/pygoogle/pygoogle-0.6.tar.gz#md5=f9053f1b7350b899811a7c9226c8a2cb (from https://pypi.python.org/simple/pygoogle/)
  Running setup.py (path:/private/tmp/pip-build-1jAoXq/pygoogle/setup.py) egg_info for package pygoogle
    Running command python setup.py egg_info
    usage: -c [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...]
       or: -c --help [cmd1 cmd2 ...]
       or: -c --help-commands
       or: -c cmd --help

    error: invalid command 'egg_info'
    Complete output from command python setup.py egg_info:
    usage: -c [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...]
       or: -c --help [cmd1 cmd2 ...]
       or: -c --help-commands
       or: -c cmd --help

    error: invalid command 'egg_info'

    ----------------------------------------
Cleaning up...
Command "python setup.py egg_info" failed with error code 1 in /private/tmp/pip-build-1jAoXq/pygoogle
Exception information:
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-7.1.0-py2.7.egg/pip/basecommand.py", line 223, in main
    status = self.run(options, args)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-7.1.0-py2.7.egg/pip/commands/install.py", line 282, in run
    requirement_set.prepare_files(finder)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-7.1.0-py2.7.egg/pip/req/req_set.py", line 334, in prepare_files
    functools.partial(self._prepare_file, finder))
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-7.1.0-py2.7.egg/pip/req/req_set.py", line 321, in _walk_req_to_install
    more_reqs = handler(req_to_install)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-7.1.0-py2.7.egg/pip/req/req_set.py", line 505, in _prepare_file
    abstract_dist.prep_for_dist()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-7.1.0-py2.7.egg/pip/req/req_set.py", line 123, in prep_for_dist
    self.req_to_install.run_egg_info()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-7.1.0-py2.7.egg/pip/req/req_install.py", line 407, in run_egg_info
    command_desc='python setup.py egg_info')
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-7.1.0-py2.7.egg/pip/utils/__init__.py", line 732, in call_subprocess
    % (command_desc, proc.returncode, cwd))
InstallationError: Command "python setup.py egg_info" failed with error code 1 in /private/tmp/pip-build-1jAoXq/pygoogle

Ich habe bereits Folgendes ausprobiert. Sie teilen mir lediglich mit, dass das Paket setuptools bereits installiert ist.

sudo pip install setuptools
sudo pip install [--upgrade] setuptools
easy_install [-U] setuptools

Bitte beachten Sie, dass die folgenden Befehle ausgegeben werden:

where python
/Library/Frameworks/Python.framework/Versions/2.7/bin/python
/usr/local/bin/python

which python
/Library/Frameworks/Python.framework/Versions/2.7/bin/python

where pip
/Library/Frameworks/Python.framework/Versions/2.7/bin/pip
/usr/local/bin/pip

which pip
/Library/Frameworks/Python.framework/Versions/2.7/bin/pip

echo $SHELL
/bin/zsh

Und mein .zprofile:

# Setting PATH for Python 2.7
# The orginal version is saved in .zprofile.pysave
PATH="/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}"
export PATH