code: def forward(self, x):
      residual = x
      x = paddle.transpose(x, perm=[0, 2, 1])
      x = self.w_2(F.relu(self.w_1(x)))
      x = paddle.transpose(x, perm=[0, 2, 1])
      x = self.dropout(x)
      x = self.layer_norm(x + residual)
      return x
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import paddle
  from paddle import ParamAttr
  import paddle.nn
  import paddle.nn.functional
  from paddle.nn.initializer import Normal, XavierNormal
  import numpy
label_desc: Use image node_id 2 for calling the PositionwiseFeedForward obj's underlying member method code with example usage: obj.forward(x) and returns: x