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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 parabolic(f, x):
 """ Interpolation. From ageobot, from somewhere else. """

    xv = 1/2. * (f[x-1] - f[x+1]) / (f[x-1] - 2 * f[x] + f[x+1]) + x
    yv = f[x] - 1/4. * (f[x-1] - f[x+1]) * (xv - x)
    return (xv, yv)