text: from cupy import _util
  
  # expose cache handles to this module
  from cupy.fft._cache import get_plan_cache  # NOQA
  from cupy.fft._cache import clear_plan_cache  # NOQA
  from cupy.fft._cache import get_plan_cache_size  # NOQA
  from cupy.fft._cache import set_plan_cache_size  # NOQA
  from cupy.fft._cache import get_plan_cache_max_memsize  # NOQA
  from cupy.fft._cache import set_plan_cache_max_memsize  # NOQA
  from cupy.fft._cache import show_plan_cache_info  # NOQA
  
  # on Linux, expose callback handles to this module
  import sys as _sys
  if _sys.platform.startswith('linux'):
      from cupy.fft._callback import get_current_callback_manager  # NOQA
      from cupy.fft._callback import set_cufft_callbacks  # NOQA
  else:
      def get_current_callback_manager(*args, **kwargs):
          return None
  
      class set_cufft_callbacks:
          def __init__(self, *args, **kwargs):
              raise RuntimeError('cuFFT callback is only available on Linux')
  
  
  enable_nd_planning = True
  use_multi_gpus = False
  _devices = None
  
  
  def set_cufft_gpus(gpus):
      '''Set the GPUs to be used in multi-GPU FFT.
  
      Args:
          gpus (int or list of int): The number of GPUs or a list of GPUs
              to be used. For the former case, the first ``gpus`` GPUs
              will be used.
  
      .. warning::
          This API is currently experimental and may be changed in the future
          version.
  
      .. seealso:: `Multiple GPU cuFFT Transforms`_
  
      .. _Multiple GPU cuFFT Transforms:
          https://docs.nvidia.com/cuda/cufft/index.html#multiple-GPU-cufft-transforms
      '''
      _util.experimental('cupy.fft.config.set_cufft_gpus')
      global _devices
  
      if isinstance(gpus, int):
          devs = list(range(gpus))
      elif isinstance(gpus, list):
          devs = gpus
      else:
          raise ValueError("gpus must be an int or a list of int.")
      if len(devs) <= 1:
          raise ValueError("Must use at least 2 GPUs.")
  
      # make it hashable
      _devices = tuple(devs)
  