k_product, default to 40, is kpoint number * length for a & b
        directions, also for c direction in bulk calculations
        Automatic mesh & Gamma is the default setting.

def kpoints(self):
        """
        k_product, default to 40, is kpoint number * length for a & b
        directions, also for c direction in bulk calculations
        Automatic mesh & Gamma is the default setting.
        """

        # To get input sets, the input structure has to has the same number
        # of required parameters as a Structure object.

        kpt = super().kpoints
        kpt.comment = "Generated by pymatgen's MVLGBSet"
        kpt.style = 'Gamma'

        # use k_product to calculate kpoints, k_product = kpts[0][0] * a
        lengths = self.structure.lattice.abc
        kpt_calc = [int(self.k_product / lengths[0] + 0.5),
                    int(self.k_product / lengths[1] + 0.5),
                    int(self.k_product / lengths[2] + 0.5)]

        if self.slab_mode:
            kpt_calc[2] = 1

        kpt.kpts[0] = kpt_calc

        return kpt