The gae_libs module is for shared code that depends on App Engine APIs (gae is short for Google App Engine), eg: an NDB model that supports keeping multiple versions of the same information like configuration.
It also depends on the sibling libs module, and provides gae wrappers for the code there, e.g., a Gitiles client with data cached in memcache on App Engine.
Create symbolic links to both gae_libs and libs in the same directory PARENT_DIR, and ensure that PARENT_DIR is in sys.path or PYTHONPATH.
The usage would look like: from gae_libs import API_MODULE_NAME