Internal Program Version: zc.lockfile  2.0

The zc.lockfile package provides a basic portable implementation of
interprocess locks using lock files. The purpose if not specifically to lock
files, but to simply provide locks with an implementation based on file-locking
primitives. Of course, these locks could be used to mediate access to other
files. For example, the ZODB file storage implementation uses file locks to
mediate access to file-storage database files. The database files and lock file
files are separate files.

https://pypi.python.org/pypi/zc.lockfile