code: def forward(self, x, H, W):
      if x.dim() == 3:
          B, N, C = x.shape
          if N == (H * W + 1):
              cls_tokens = x[:, 0, :]
              x_ = (
                  x[:, 1:, :].transpose([0, 2, 1]).reshape([B, C, H, W])
              )
          else:
              x_ = x.transpose([0, 2, 1]).reshape([B, C, H, W])
  
          x_ = self.fc1(x_)
          x_ = self.act1(x_)
          x_ = self.dw3x3(x_)
          x_ = self.act2(x_)
          x_ = self.fc2(x_)
          x_ = self.act3(x_)
          x_ = x_.reshape([B, C, -1]).transpose([0, 2, 1])
          if N == (H * W + 1):
              x = paddle.concat((cls_tokens.unsqueeze(1), x_), axis=1)
          else:
              x = x_
          return x
  
      elif x.dim() == 4:
          x = self.fc1(x)
          x = self.act1(x)
          x = self.dw3x3(x)
          x = self.act2(x)
          x = self.fc2(x)
          x = self.act3(x)
          return x
  
      else:
          raise RuntimeError(f"Unsupported input shape: {x.shape}")
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddleseg.cvlibs import manager, param_init
  from paddleseg.models import layers
  from paddleseg.utils import utils, logger
  from paddleseg.models.backbones.transformer_utils import *
label_desc: Use image node_id 2 for calling the MlpDWBN obj's underlying member method code with example usage: obj.forward(x, H, W) and returns: x, x