Python error on MacOS

Python error on MacOS

~$sudo pip install django --upgrade
Downloading/unpacking django
  Downloading Django-1.2.5.tar.gz (6.4Mb): 6.4Mb downloaded
  Running setup.py egg_info for package django
Installing collected packages: django
  Running setup.py install for django
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/Users/arihershowitz/build/django/setup.py", line 96, in <module>
        'Topic :: Software Development :: Libraries :: Python Modules',
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/distutils/core.py", line 152, in setup
        dist.run_commands()
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/distutils/dist.py", line 975, in run_commands
        self.run_command(cmd)
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/distutils/dist.py", line 994, in run_command
        cmd_obj.ensure_finalized()
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/distutils/cmd.py", line 117, in ensure_finalized
        self.finalize_options()
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/setuptools/command/install.py", line 32, in finalize_options
        _install.finalize_options(self)
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/distutils/command/install.py", line 344, in finalize_options
        self.expand_dirs()
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/distutils/command/install.py", line 522, in expand_dirs
        'install_data',])
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/distutils/command/install.py", line 507, in _expand_attrs
        val = subst_vars(val, self.config_vars)
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/distutils/util.py", line 259, in subst_vars
        raise ValueError, "invalid variable '$%s'" % var
    ValueError: invalid variable '$'py''
    Complete output from command /usr/bin/python -c "import setuptools;__file__='/Users/arihershowitz/build/django/setup.py';execfile(__file__)" install --single-version-externally-managed --record /tmp/pip-_5pOtc-record/install-record.txt:
    running install