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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 get_final_from_initial(mass1, mass2, spin1x=0., spin1y=0., spin1z=0., spin2x=0., spin2y=0., spin2z=0., approximant='SEOBNRv4'):
 """Estimates the final mass and spin from the given initial parameters. This uses the fits used by the EOBNR models for converting from initial parameters to final. Which version used can be controlled by the ``approximant`` argument. Parameters mass1 : float The mass of one of the components, in solar masses. mass2 : float The mass of the other component, in solar masses. spin1x : float, optional The dimensionless x-component of the spin of mass1. Default is 0. spin1y : float, optional The dimensionless y-component of the spin of mass1. Default is 0. spin1z : float, optional The dimensionless z-component of the spin of mass1. Default is 0. spin2x : float, optional The dimensionless x-component of the spin of mass2. Default is 0. spin2y : float, optional The dimensionless y-component of the spin of mass2. Default is 0. spin2z : float, optional The dimensionless z-component of the spin of mass2. Default is 0. approximant : str, optional The waveform approximant to use for the fit function. Default is "SEOBNRv4". Returns ------- final_mass : float The final mass, in solar masses. final_spin : float The dimensionless final spin. """

    args = (mass1, mass2, spin1x, spin1y, spin1z, spin2x, spin2y, spin2z)
    args = ensurearray(*args)
    input_is_array = args[-1]
    origshape = args[0].shape
    # flatten inputs for storing results
    args = [a.ravel() for a in args[:-1]]
    mass1, mass2, spin1x, spin1y, spin1z, spin2x, spin2y, spin2z = args
    final_mass = numpy.zeros(mass1.shape)
    final_spin = numpy.zeros(mass1.shape)
    for ii in range(final_mass.size):
        m1 = mass1[ii]
        m2 = mass2[ii]
        spin1 = [spin1x[ii], spin1y[ii], spin1z[ii]]
        spin2 = [spin2x[ii], spin2y[ii], spin2z[ii]]
        _, fm, fs = lalsim.SimIMREOBFinalMassSpin(m1, m2, spin1, spin2,
                                                  getattr(lalsim, approximant))
        final_mass[ii] = fm * (m1 + m2)
        final_spin[ii] = fs
    final_mass = final_mass.reshape(origshape)
    final_spin = final_spin.reshape(origshape)
    return (formatreturn(final_mass, input_is_array),
            formatreturn(final_spin, input_is_array))