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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 image_set_aspect(aspect=1.0, axes="gca"):
 """ sets the aspect ratio of the current zoom level of the imshow image """

    if axes is "gca": axes = _pylab.gca()

    e = axes.get_images()[0].get_extent()
    axes.set_aspect(abs((e[1]-e[0])/(e[3]-e[2]))/aspect)