class_docstr: Decoder is made of self attention, srouce attention and feed forward.
code: def forward(self, x, feature, src_mask, tgt_mask):
      x = self.sublayer[0](
          x, lambda x: self.self_attn(x, x, x, tgt_mask)
      )
      x = self.sublayer[1](
          x, lambda x: self.src_attn(x, feature, feature, src_mask)
      )
      return self.sublayer[2](x, self.feed_forward)
  
imports: import copy
  import math
  import paddle
  from paddle import nn
  from paddle.nn import functional
label_desc: Use image node_id 2 for calling the DecoderLayer obj's underlying member method code with example usage: obj.forward(x, feature, src_mask, tgt_mask) and returns: self