code: def Unlock(fd, path):
    
    try:
      fcntl.flock(fd, fcntl.LOCK_UN | fcntl.LOCK_NB)
    except IOError as e:
      if e.errno == errno.EWOULDBLOCK:
        raise IOError('Exception unlocking %s. Locked by another process.' % path)
      else:
        raise IOError('Exception unlocking %s. %s.' % (path, str(e)))
docs: Release the lock on the file.
  
    Args:
      fd: int, the file descriptor of the file to unlock.
      path: string, the name of the file to lock.
  
    Raises:
      IOError, raised from flock while attempting to release a file lock.