human
Here's a good function header given the following:
I wrote the below code

    def same_fs(filename_a, filename_b):
        '\n                                Checks    if    both    files    reside    on    the\n                                same    FS    device\n                                '
        stats_a = os.stat(filename_a)
        stats_b = os.stat(filename_b)
        return (stats_a.st_dev == stats_b.st_dev)
    if (os.path.exists(dst_filename) and (not same_fs(src_filename, dst_filename))):
        dst_path = os.path.dirname(os.path.abspath(dst_filename))
        dst_temp_filename = os.tempnam(dst_path)
        shutil.copy(src_filename, dst_temp_filename)
        shutil.move(dst_temp_filename, dst_filename)
    else:
        shutil.move(src_filename, dst_filename)

What's a good function header?
assistant
#Here's a good function header.

def atomic_replace(src_filename, dst_filename):