code: def forward(self, x):
      if self.stem:
          x = self.stem_block(x)
      for _, layer_name in enumerate(self.layers):
          layer = getattr(self, layer_name)
          x = layer(x)
      return x
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddleseg.cvlibs import manager, param_init
  from paddleseg.models import layers
  from paddleseg.models.backbones.transformer_utils import DropPath, zeros_, ones_
  from paddleseg.utils import utils
label_desc: Use image node_id 2 for calling the StackedMV2Block obj's underlying member method code with example usage: obj.forward(x) and returns: x