code: def _erfc_expected(x, dtype):
      if backend.get_array_module(x) is numpy:
          return _erfc_cpu(x, dtype)
      else:
          return _erfc_gpu(x, dtype)
  
file_path: chainer/tests/chainer_tests/functions_tests/math_tests/test_erfc.py
imports: import math
  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 3 for calling a global function with example usage: _erfc_expected(x, dtype) and returns: _erfc_cpu, _erfc_gpu