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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_art(cache_dir, size, client):
 """Get the album art."""

    song = client.currentsong()

    if len(song) < 2:
        print("album: Nothing currently playing.")
        return

    file_name = f"{song['artist']}_{song['album']}_{size}.jpg".replace("/", "")
    file_name = cache_dir / file_name

    if file_name.is_file():
        shutil.copy(file_name, cache_dir / "current.jpg")
        print("album: Found cached art.")

    else:
        print("album: Downloading album art...")

        brainz.init()
        album_art = brainz.get_cover(song, size)

        if album_art:
            util.bytes_to_file(album_art, cache_dir / file_name)
            util.bytes_to_file(album_art, cache_dir / "current.jpg")

            print(f"album: Swapped art to {song['artist']}, {song['album']}.")