code: def d_hkl(self, miller_index: Vector3Like) -> float:
          
  
          gstar = self.reciprocal_lattice_crystallographic.metric_tensor
          hkl = np.array(miller_index)
          return 1 / ((dot(dot(hkl, gstar), hkl.T)) ** (1 / 2))
docs: Returns the distance between the hkl plane and the origin
  
          Args:
              miller_index ([h,k,l]): Miller index of plane
  
          Returns:
              d_hkl (float)