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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 prox_lim(xy, step, boundary=None):
 """Proximal projection operator"""

    if boundary == "circle":
        return prox_circle(xy, step)
    if boundary == "line":
        return prox_line(xy, step)
    # default: do nothing
    return xy