code: def check_cuda_available():
      """Checks if CUDA is available.
  
      When CUDA is correctly set up, nothing happens.
      Otherwise it raises ``RuntimeError``.
      """
      if not available:
          msg = (
              "CUDA environment is not correctly set up\n"
              "(see https://github.com/chainer/chainer#installation)."
          )
          msg += str(_resolution_error)
          raise RuntimeError(msg)
      if (
          not cudnn_enabled
          and not _cudnn_disabled_by_user
          and not getattr(
              check_cuda_available, "_already_warned", False
          )
      ):
          warnings.warn(
              "cuDNN is not enabled.\n"
              "Please reinstall CuPy after you install cudnn\n"
              "(see https://docs-cupy.chainer.org/en/stable/install.html"
              "#install-cudnn)."
          )
          check_cuda_available._already_warned = True
  
imports: import binascii
  import functools
  import itertools
  import os
  import threading
  import time
  import typing
  import warnings
  import numpy
  import six
  import chainer
  from chainer import _backend
  from chainer.backends import _cpu
  from chainer.backends import intel64
  from chainer.configuration import config
  from chainer import types
  import chainerx
label_desc: Use image node_id 1 for calling a global function with example usage: check_cuda_available() without return types