code: def forward_expected(self, inputs):
      def _extract_gates(x, n_split=5):
          r = x.reshape(
              (x.shape[0], n_split, x.shape[1] // n_split) + x.shape[2:]
          )
          return [r[:, i, :] for i in six.moves.range(n_split)]
  
      cs, x = inputs[:-1], inputs[-1]
      n_ary = len(cs)
      gates = _extract_gates(x, 3 + n_ary)
      a, i, o = gates[:3]
      fs = gates[3:]
      a = numpy.tanh(a)
      i = _sigmoid(i)
      o = _sigmoid(o)
      fs = [_sigmoid(f) for f in fs]
      c = a * i + sum(f * c for f, c in zip(fs, cs))
      h = o * numpy.tanh(c)
      return c, h
  
file_path: chainer/tests/chainer_tests/functions_tests/rnn_tests/test_function_tree_lstm.py
imports: import numpy
  import six
  from chainer import functions
  from chainer import testing
  from chainer.testing import backend
label_desc: Use image node_id 4 for calling the TestTreeLSTM obj's underlying member method code with example usage: obj.forward_expected(inputs) and returns: c,  h, unknown