code: def forward(self, x):
      y = self.layers[0](x)
      for layer in self.layers[1:]:
          if isinstance(y, tuple):
              y = y[0]
          y = layer(y)
  
      if self.skip is not None:
          skip = self.skip(x)
          skip = self.skipbn(skip)
      else:
          skip = x
      y = self.add(y, skip)
      return y
  
file_path: singa/examples/cifar_distributed_cnn/autograd/xceptionnet.py
imports: from singa import autograd
  from singa import tensor
  from singa import device
  from singa import layer
  from singa import opt
  import numpy
  from tqdm import trange
label_desc: Use image node_id 2 for calling the Block obj's underlying member method code with example usage: obj.forward(x) and returns: y