code: def forward(self, images):
      out = self.backbone(images)
      return self.projection_head(out)
  
file_path: lightly/examples/pytorch/msn.py
imports: import copy
  import torch
  import torchvision
  from torch import nn
  from lightly.loss import MSNLoss
  from lightly.models import utils
  from lightly.models.modules.heads import MSNProjectionHead
  from lightly.models.modules.masked_autoencoder import MAEBackbone
  from lightly.transforms.msn_transform import MSNTransform
label_desc: Use image node_id 2 for calling the MSN obj's underlying member method code with example usage: obj.forward(images) and returns: self