code: def forward(self, *args):
      src = args[0]
      src_mask = args[1]
      src = self.encoder(src) * math.sqrt(self.ninp)
      src = self.pos_encoder(src)
      output = self.transformer_encoder(src, src_mask)
      output = self.decoder(output)
      return output
  
imports: import math
  import sys
  import pytest
  import torch
  import torch.nn
  import torch.nn
  from fairscale.internal import torch_version
label_desc: Use image node_id 4 for calling the TransformerModel obj's underlying member method code with example usage: obj.forward() and returns: output