code: def forward(
      self,
      src,
      src_mask: Optional[Tensor] = None,
      src_key_padding_mask: Optional[Tensor] = None,
      pos: Optional[Tensor] = None,
  ):
      if self.normalize_before:
          return self.forward_pre(
              src, src_mask, src_key_padding_mask, pos
          )
      return self.forward_post(src, src_mask, src_key_padding_mask, pos)
  
imports: import copy
  from typing import Optional
  import torch
  import torch.nn.functional
  from torch import nn, Tensor
label_desc: Use image node_id 5 for calling the TransformerEncoderLayer obj's underlying member method code with example usage: obj.forward(src, src_mask, src_key_padding_mask, pos) and returns: self, self