code: def check_available():
      if _error is not None:
          raise RuntimeError(
              """\
  {} is not available.
  
  Reason: {}: {}""".format(
                  __name__, type(_error).__name__, _error
              )
          )
  
file_path: chainer/chainer/testing/unary_math_function_test.py
imports: import unittest
  import warnings
  import numpy
  from chainer.backends import cuda
  from chainer import function
  from chainer import functions
  from chainer import variable
label_desc: Use image node_id 2 for calling a global function with example usage: check_available() without return types