class_docstr: A multilayer perceptron.
  
  Args:
      n_vocab (int): The size of vocabulary.
      n_units (int): The number of units in a hidden or output layer.
      dropout (float): The dropout ratio.
code: def forward(self, x):
      for i, link in enumerate(self.children()):
          x = F.dropout(x, ratio=self.dropout)
          x = F.relu(link(x))
      return x
  
imports: import numpy
  import chainer
  import chainer.functions
  import chainer.links
  from chainer import reporter
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: x