code: def _zoneout(h, x, creator):
      h_next = h * creator.flag_h + x * creator.flag_x
      return h_next
  
imports: import unittest
  import mock
  import numpy
  import chainer
  from chainer import backend
  from chainer.backends import cuda
  from chainer import functions
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 1 for calling a global function with example usage: _zoneout(h, x, creator) and returns: h_next