code: def forward(self, x):
      x = x + self.attention(self.ln_1(x))
      x = x + self.mlp(self.ln_2(x))
      return x
  
imports: from typing import Optional
  import paddle
  import paddle.nn
  from paddle import Tensor
  from paddle.nn import functional
  from paddle.nn import Linear
label_desc: Use image node_id 3 for calling the ResidualAttentionBlock obj's underlying member method code with example usage: obj.forward(x) and returns: x