code: def forward_expected(self, inputs):
      c_prev1, c_prev2, x1, x2 = inputs
  
      def _extract_gates(x):
          r = x.reshape((x.shape[0], x.shape[1] // 4, 4) + x.shape[2:])
          return (r[:, :, i] for i in six.moves.range(4))
  
      a1_in, i1_in, f1_in, o1_in = _extract_gates(x1)
      a2_in, i2_in, f2_in, o2_in = _extract_gates(x2)
  
      c_expect = (
          _sigmoid(i1_in) * numpy.tanh(a1_in)
          + _sigmoid(i2_in) * numpy.tanh(a2_in)
          + _sigmoid(f1_in) * c_prev1
          + _sigmoid(f2_in) * c_prev2
      )
      h_expect = _sigmoid(o1_in + o2_in) * numpy.tanh(c_expect)
      return c_expect, h_expect
  
imports: import unittest
  import numpy
  import six
  from chainer.backends import cuda
  from chainer import functions
  from chainer.functions.rnn import slstm
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import backend
label_desc: Use image node_id 4 for calling the TestSLSTM obj's underlying member method code with example usage: obj.forward_expected(inputs) and returns: c_expect,  h_expect, unknown