python-lockfile 1:0.8-2ubuntu2 (i386 binary) in ubuntu utopic

 The ‘lockfile’ module exports a ‘FileLock’ class which provides a
 simple API for locking files.
 .
 The appropriate implementation for ‘FileLock’ is chosen automatically
 based on the OS capabilities for an atomic filesystem operation.
 These implementations are also available for explicit use as
 ‘LinkFileLock’ and ‘MkdirFileLock’.
 .
 Other back ends are possible with the same semantics; an example
 provided is ‘SQLiteFileLock’.
 .
 Unlike other Python locking libraries (the Windows ‘msvcrt.locking’
 function, the Unix ‘fcntl.flock’, ‘fcntl.lockf’, and the deprecated
 ‘posixfile’ module), the API is identical across both Unix (including
 GNU/Linux and MacOS) and Windows platforms.