class_docstr: Multi-Layer Perceptron
code: def forward(self, x):
      h = x
      if self.hidden_sizes:
          for layer in self.hidden_layers:
              h = self.nonlinearity(layer(h))
      return self.output(h)
  
imports: import torch.nn
  import torch.nn.functional
  from pfrl.initializers import init_chainer_default, init_lecun_normal
label_desc: Use image node_id 2 for calling the MLP obj's underlying member method code with example usage: obj.forward(x) and returns: self