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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_kpoints(self, line_density=20, cart_coords=False, phonopy=False):
 r"""Return a list of k-points and labels along the high-symmetry path. The format of the returned data will be different if phonopy is ``True`` or ``False``. This is because phonopy requires the labels and kpoints to be provided in a different format than kgen. Adapted from :obj:`pymatgen.symmetry.bandstructure.HighSymmKpath.get_kpoints`. Args: line_density (:obj:`int`, optional):
 Density of k-points along the path. cart_coords (:obj:`bool`, optional):
 Whether the k-points are returned in cartesian or reciprocal coordinates. Defaults to ``False`` (fractional coordinates). phonopy (:obj:`bool`, optional):
 Format the k-points and labels for use with phonopy. Defaults to ``False``. Returns: tuple: A :obj:`tuple` of the k-points along the high-symmetry path, and k-point labels. Returned as ``(kpoints, labels)``. If ``phonopy == False``, then: * ``kpoints`` is a :obj:`numpy.ndarray` of the k-point coordinates along the high-symmetry path. For example:: [[0, 0, 0], [0.25, 0, 0], [0.5, 0, 0], [0.5, 0, 0.25], [0.5, 0, 0.5]] * ``labels`` is a :obj:`list` of the high symmetry labels for each k-point (will be an empty :obj:`str` if the k-point has no label). For example:: ['\Gamma', '', 'X', '', 'Y'] If ``phonopy == True``, then: * ``kpoints`` is a :obj:`list` of :obj:`numpy.ndarray` containing the k-points for each branch of the band structure. This means that the first and last k-points of a particular branch may be repeated. For example:: [[[0, 0, 0], [0.25, 0, 0], [0.5, 0, 0]], [[0.5, 0, 0], [0.5, 0, 0.25], [0.5, 0, 0.5]]] * ``labels`` is a :obj:`list` of the high symmetry labels. For example:: ['\Gamma', 'X', 'Y'] """

        list_k_points = []
        sym_point_labels = []
        recip_lattice = self.structure.lattice.reciprocal_lattice
        for b in self.path:
            for i in range(1, len(b)):
                start = np.array(self.kpoints[b[i - 1]])
                end = np.array(self.kpoints[b[i]])
                distance = np.linalg.norm(
                    recip_lattice.get_cartesian_coords(start) -
                    recip_lattice.get_cartesian_coords(end))
                nb = int(np.ceil(distance * line_density))
                sym_point_labels.extend([b[i - 1]] + [''] * (nb - 1))

                limit = nb + 1 if phonopy else nb
                kpts = [recip_lattice.get_cartesian_coords(start)
                        + float(i) / float(nb) *
                        (recip_lattice.get_cartesian_coords(end)
                        - recip_lattice.get_cartesian_coords(start))
                        for i in range(0, limit)]

                if phonopy:
                    list_k_points.append(kpts)
                else:
                    list_k_points.extend(kpts)

            # append last k-point to avoid repetition as in pymatgen
            if not phonopy:
                # for VASP we label every k-point. If a k-point has no
                # high-symmetry label then just use an empty string.
                sym_point_labels.append(b[-1])
                list_k_points.append(recip_lattice.get_cartesian_coords(end))

        if phonopy:
            # For phonopy, the labels for any discontinuities should be
            # combined. For example if the route is  X -> Y | Z -> R, the path
            # will be [['X', 'Y'], ['Z', 'R']], and the labels should be
            # ['X', 'Z', 'R']

            sym_point_labels = []
            for i, path_branch in enumerate(self.path):
                for n, label in enumerate(path_branch):
                    if i != 0 and n == 0:
                        sym_point_labels[-1] += " | {}".format(label)
                    else:
                        sym_point_labels.append(label)

        if cart_coords:
            return list_k_points, sym_point_labels
        else:
            if phonopy:
                frac_k_points = [[recip_lattice.get_fractional_coords(k)
                                 for k in p] for p in list_k_points]
                frac_k_points = frac_k_points
            else:
                frac_k_points = [recip_lattice.get_fractional_coords(k)
                                 for k in list_k_points]
            return frac_k_points, sym_point_labels