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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_layers(self, Psurf=1013.25, Ptop=0.01, **kwargs):
 """ Compute scalars or coordinates associated to the vertical layers. Parameters grid_spec : CTMGrid object CTMGrid containing the information necessary to re-construct grid levels for a given model coordinate system. Returns ------- dictionary of vertical grid components, including eta (unitless), sigma (unitless), pressure (hPa), and altitude (km) on both layer centers and edges, ordered from bottom-to-top. Notes ----- For pure sigma grids, sigma coordinates are given by the esig (edges) and csig (centers). For both pure sigma and hybrid grids, pressures at layers edges L are calculated as follows: .. math:: P_e(L) = A_p(L) + B_p(L) * (P_{surf} - C_p) where :math:`P_{surf}`, :math:`P_{top}` Air pressures at the surface and the top of the modeled atmosphere (:attr:`Psurf` and :attr:`Ptop` attributes of the :class:`CTMGrid` instance). :math:`A_p(L)`, :math:`Bp(L)` Specified in the grid set-up (`Ap` and `Bp` attributes) for hybrid grids, or respectively equals :math:`P_{top}` and :attr:`esig` attribute for pure sigma grids. :math:`Cp(L)` equals :math:`P_{top}` for pure sigma grids or equals 0 for hybrid grids. Pressures at grid centers are averages of pressures at grid edges: .. math:: P_c(L) = (P_e(L) + P_e(L+1)) / 2 For hybrid grids, ETA coordinates of grid edges and grid centers are given by; .. math:: ETA_{e}(L) = (P_e(L) - P_{top}) / (P_{surf} - P_{top}) .. math:: ETA_{c}(L) = (P_c(L) - P_{top}) / (P_{surf} - P_{top}) Altitude values are fit using a 5th-degree polynomial; see `gridspec.prof_altitude` for more details. """


        Psurf = np.asarray(Psurf)
        output_ndims = Psurf.ndim + 1
        if output_ndims > 3:
            raise ValueError("`Psurf` argument must be a float or an array"
                             " with <= 2 dimensions (or None)")

        # Compute all variables: takes not much memory, fast
        # and better for code reading
        SIGe = None
        SIGc = None
        ETAe = None
        ETAc = None

        if self.hybrid:
            try:
                Ap = broadcast_1d_array(self.Ap, output_ndims)
                Bp = broadcast_1d_array(self.Bp, output_ndims)
            except KeyError:
                raise ValueError("Impossible to compute vertical levels,"
                                 " data is missing (Ap, Bp)")
            Cp = 0.
        else:
            try:
                Bp = SIGe = broadcast_1d_array(self.esig, output_ndims)
                SIGc = broadcast_1d_array(self.csig, output_ndims)
            except KeyError:
                raise ValueError("Impossible to compute vertical levels,"
                                 " data is missing (esig, csig)")
            Ap = Cp = Ptop

        Pe = Ap + Bp * (Psurf - Cp)
        Pc = 0.5 * (Pe[0:-1] + Pe[1:])

        if self.hybrid:
            ETAe = (Pe - Ptop)/(Psurf - Ptop)
            ETAc = (Pc - Ptop)/(Psurf - Ptop)
        else:
            SIGe = SIGe * np.ones_like(Psurf)
            SIGc = SIGc * np.ones_like(Psurf)

        Ze = prof_altitude(Pe, **kwargs)
        Zc = prof_altitude(Pc, **kwargs)

        all_vars = {'eta_edges': ETAe,
                    'eta_centers': ETAc,
                    'sigma_edges': SIGe,
                    'sigma_centers': SIGc,
                    'pressure_edges': Pe,
                    'pressure_centers': Pc,
                    'altitude_edges': Ze,
                    'altitude_centers': Zc}

        return all_vars