What does it mean when a package is installed as "non-active development"?

For whatever reason, my build system isn't installing one of my packages properly. When I use yolk (from within a virtualenv), I get the following:

bin/yolk -l elig
elig            - 3.1.2.dev    - non-active development (/home/jason/src/interface_dev/elig)

How exactly does a package go from activ开发者_开发问答e development to non-active development?

Looking through yolk source I found this:

*"The following options show information about installed Python packages. Activated packages are normal packages on sys.path that can be imported. Non-activated packages need 'pkg_resources.require()' before they can be imported, such as packages installed with 'easy_install --multi-version'. PKG_SPEC can be either a package name or package name and version e.g. Paste==0.9",

for non activated i found: *'List non-activated packages installed by distutils or setuptools. Use PKG_SPEC to narrow results.'

and for activated: *'List activated packages installed by distutils or setuptools. Use PKG_SPEC to narrow results.'

Hope that satisfies your needs or atleast helps you ;). There seem to be very little documentation on this online.
* found in http://trac.assembla.com/yolk/browser/trunk/yolk/cli.py