code: def inject_backend_tests(method_names):
      decorator = backend.inject_backend_tests(
          method_names,
          # CPU tests
          testing.product(
              {
                  "use_cuda": [False],
                  "use_ideep": ["never", "always"],
              }
          )
          +
          # GPU tests
          [{"use_cuda": True}],
      )
      return decorator
  
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 2 for calling a global function with example usage: inject_backend_tests(method_names) and returns: decorator