dependency resolution pip virtualenv
Using pip + virtualenv you can't have two versions of a library installed at the same time.
And, unfortunately, I don't know of any good ways of handling this situation. Sorry.
I have 2 local libraries which are dependent on different version of suds. 
Example - 

Module-A-1.0's setup.py has a requirement of suds ==0.3.9. 
Module-B-1.0's setup.py has a requirement of suds ==0.4.0. 

Both these modules are required by Module-C, which has the following its setup.py

django
Module-A-1.0
Module-B-1.0

Module-C will be installed in a virtualenv using pip. My question is which version of suds will be installed and can I have both versions installed in the same virtual env?
What I noticed was, whichever module I specified first in the setup.py for Module-C, that version of suds gets installed. So in this case suds 0.3.9. If I switched the modules to 

django
Module-B-1.0
Module-A-1.0

The version of suds that gets installed in suds-0.4.0.