code: def forward(
      self,
      tgt,
      tgt_mask: Optional[Tensor] = None,
      tgt_key_padding_mask: Optional[Tensor] = None,
      query_pos: Optional[Tensor] = None,
  ):
      if self.normalize_before:
          return self.forward_pre(
              tgt, tgt_mask, tgt_key_padding_mask, query_pos
          )
      return self.forward_post(
          tgt, tgt_mask, tgt_key_padding_mask, query_pos
      )
  
imports: import copy
  import math
  from typing import Optional
  import torch
  import torch.nn.functional
  from torch import Tensor, nn
label_desc: Use image node_id 6 for calling the SelfAttentionLayer obj's underlying member method code with example usage: obj.forward(tgt, tgt_mask, tgt_key_padding_mask, query_pos) and returns: self, self