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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 elekta_icon_fbp(ray_transform, padding=False, filter_type='Hann', frequency_scaling=0.6, parker_weighting=True):
 """Approximation of the FDK reconstruction used in the Elekta Icon. Parameters ray_transform : `RayTransform` The ray transform to be used, should have an Elekta Icon geometry. padding : bool, optional Whether the FBP filter should use padding, increases memory use significantly. filter_type : str, optional Type of filter to apply in the FBP filter. frequency_scaling : float, optional Frequency scaling for FBP filter. parker_weighting : bool, optional Whether Parker weighting should be applied to compensate for partial scan. Returns ------- elekta_icon_fbp : `DiscreteLp` Examples -------- Create default FBP for default geometry: """

    fbp_op = odl.tomo.fbp_op(ray_transform,
                             padding=padding,
                             filter_type=filter_type,
                             frequency_scaling=frequency_scaling)
    if parker_weighting:
        parker_weighting = odl.tomo.parker_weighting(ray_transform)
        fbp_op = fbp_op * parker_weighting

    return fbp_op