docs: def _update_mean_coords(self, dig, N, centers_sum, **paircoords):
          """
          Update the mean coordinate sums
          """
          if N is None or centers_sum is None: return
  
          N.flat[:] += utils.bincount(dig, 1., minlength=N.size)
          for i, dim in enumerate(self.dims):
              size = centers_sum[i].size
              centers_sum[i].flat[:] += utils.bincount(dig, paircoords[dim], minlength=size)