Installing specific package versions with pip
 I'm trying to install version 1.2.2 of the MySQL_python adaptor, using a fresh virtualenv created with the --no-site-packages option.  The current version shown in PyPi is 1.2.3.  Is there a way to install the older version?  I found an article stating that this should do it:  
pip install MySQL_python==1.2.2
When installed, however, it still shows MySQL_python-1.2.3-py2.6.egg-info in the site packages. Is this a problem specific to this package, or am I doing something wrong?
 First, I see two issues with what you're trying to do.  Since you already have an installed version, you should either uninstall the current existing driver or use pip install -I MySQL_python==1.2.2  
 However, you'll soon find out that this doesn't work.  If you look at pip's installation log, or if you do a pip install -Iv MySQL_python==1.2.2 you'll find that the PyPI URL link does not work for MySQL_python v1.2.2.  You can verify this here: http://pypi.python.org/pypi/MySQL-python/1.2.2  
The download link 404s and the fallback URL links are re-directing infinitely due to sourceforge.net's recent upgrade and PyPI's stale URL.
So to properly install the driver, you can follow these steps:
pip uninstall MySQL_python
pip install -Iv http://sourceforge.net/projects/mysql-python/files/mysql-python/1.2.2/MySQL-python-1.2.2.tar.gz/download
 You can even use a version range with pip install command.  Something like this:  
pip install 'stevedore>=1.3.0,<1.4.0'
 One way as suggested in this post is to mention version in pip as  
 pip install -Iv MySQL_python==1.2.2 
 ie Use == and mention the version number to install only that version.  -I, --ignore-installed ignores already installed packages.  
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