def METHOD_NAME(img, window, level, maxc=255):
    """Change window and level data in image.
    :param img: numpy array representing an image
    :param window: the window for the transformation
    :param level: the level for the transformation
    :param maxc: what the maximum display color is
    """
    m = maxc / (2.0 * window)
    o = m * (level - window)
    return np.clip((m * img - o), 0, maxc).astype(np.uint8)