code: def forward(self, x):
      hx = x
  
      hxin = self.rebnconvin(hx)
  
      hx1 = self.rebnconv1(hxin)
      hx = self.pool1(hx1)
  
      hx2 = self.rebnconv2(hx)
      hx = self.pool2(hx2)
  
      hx3 = self.rebnconv3(hx)
  
      hx4 = self.rebnconv4(hx3)
  
      hx3d = self.rebnconv3d(paddle.concat((hx4, hx3), 1))
      hx3dup = _upsample_like(hx3d, hx2)
  
      hx2d = self.rebnconv2d(paddle.concat((hx3dup, hx2), 1))
      hx2dup = _upsample_like(hx2d, hx1)
  
      hx1d = self.rebnconv1d(paddle.concat((hx2dup, hx1), 1))
  
      return hx1d + hxin
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddleseg.cvlibs import manager
  from paddleseg.models import layers
  from paddleseg.utils import utils
label_desc: Use image node_id 2 for calling the RSU4 obj's underlying member method code with example usage: obj.forward(x) and returns: unknown