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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 keypoint_scale(keypoint, scale_x, scale_y, **params):
 """Scales a keypoint by scale_x and scale_y."""

    x, y, a, s = keypoint
    return [x * scale_x, y * scale_y, a, s * max(scale_x, scale_y)]