code: def kpoints(self):
          
  
          # 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
docs: 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.