code: def _erfcx_gpu(x, dtype):
      return cuda.to_gpu(_erfcx_cpu(cuda.to_cpu(x), dtype))
  
file_path: chainer/tests/chainer_tests/functions_tests/math_tests/test_erfcx.py
imports: import unittest
  import numpy
  from chainer import backend
  from chainer.backends import cuda
  import chainer.functions
  from chainer import testing
label_desc: Use image node_id 2 for calling a global function with example usage: _erfcx_gpu(x, dtype) and returns: cuda