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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 validate_known_curve():
 """Validate on a sin function."""

    plt.figure()
    N = 100
    x = numpy.linspace(-1, 1, N)
    y = numpy.sin(4 * x)
    smoother.DEFAULT_BASIC_SMOOTHER = smoother.BasicFixedSpanSmootherSlowUpdate
    smooth = smoother.perform_smooth(x, y, smoother_cls=supersmoother.SuperSmoother)
    plt.plot(x, smooth.smooth_result, label='Slow')
    smoother.DEFAULT_BASIC_SMOOTHER = smoother.BasicFixedSpanSmoother
    smooth = smoother.perform_smooth(x, y, smoother_cls=supersmoother.SuperSmoother)
    plt.plot(x, smooth.smooth_result, label='Fast')
    plt.plot(x, y, '.', label='data')
    plt.legend()
    plt.show()