code: def test_lstm_gpu(self):
      self._test_lstm(gpu=0)
  
imports: import unittest
  from chainer import links
  from chainer import testing
  import numpy
  from chainerrl.links import stateless_recurrent
label_desc: Use image node_id 2 for calling the TestCallRecurrentLink obj's underlying member method code with example usage: obj.test_lstm_gpu() without return types