code: def mgu(W_f, W_h, h, x):
      f = sigmoid(numpy.concatenate([h, x]).dot(W_f.T))
      hx = numpy.concatenate([f * h, x])
      h_bar = numpy.tanh(hx.dot(W_h.T))
      h_new = f * h_bar + (1 - f) * h
      return h_new
  
imports: import unittest
  import numpy
  import six
  import chainer
  from chainer.backends import cuda
  from chainer import links
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 2 for calling a global function with example usage: mgu(W_f, W_h, h, x) and returns: h_new