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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_next_image(img_dir):
 """Get the next image in a dir."""

    images, current_wall = get_image_dir(img_dir)
    images.sort(key=lambda img: [int(x) if x.isdigit() else x
                                 for x in re.split('([0-9]+)', img)])

    try:
        next_index = images.index(current_wall) + 1

    except ValueError:
        next_index = 0

    try:
        image = images[next_index]

    except IndexError:
        image = images[0]

    return os.path.join(img_dir, image)