code: def add_densification_stats(
      self, viewspace_point_tensor, update_filter
  ):
      self.xyz_gradient_accum[update_filter] += torch.norm(
          viewspace_point_tensor.grad[update_filter, :2],
          dim=-1,
          keepdim=True,
      )
      self.denom[update_filter] += 1
  
imports: import torch
  import numpy
  from utils.general_utils import inverse_sigmoid, get_expon_lr_func, build_rotation
  from torch import nn
  import os
  from utils.system_utils import mkdir_p
  from plyfile import PlyData, PlyElement
  from utils.sh_utils import RGB2SH
  from simple_knn._C import distCUDA2
  from utils.graphics_utils import BasicPointCloud
  from utils.general_utils import strip_symmetric, build_scaling_rotation
label_desc: Use image node_id 27 for calling the GaussianModel obj's underlying member method code with example usage: obj.add_densification_stats(viewspace_point_tensor, update_filter) without return types