def METHOD_NAME(self):
    # again, but pass the file rather than numeric descriptor
    self.f = open(TESTFN, 'w')
    rv = fcntl.fcntl(self.f, fcntl.F_SETFL, os.O_NONBLOCK)
    if sys.platform not in ['os2emx']:
        rv = fcntl.fcntl(self.f, fcntl.F_SETLKW, lockdata)
    self.f.close()