code: def forward(self, x):
      if self.normalize_inputs is not None:
          if self.normalize_inputs == NORMALIZE_L2:
              x = nn.functional.normalize(x, p=2.0, dim=1)
      return self.layers(x)
  
file_path: ClassyVision/classy_vision/heads/vision_transformer_head.py
imports: import copy
  from collections import OrderedDict
  from typing import Optional
  import torch.nn
  from classy_vision.heads import ClassyHead, register_head
  from ..models.lecun_normal_init import lecun_normal_init
label_desc: Use image node_id 4 for calling the VisionTransformerHead obj's underlying member method code with example usage: obj.forward(x) and returns: self