code: 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 = [i for i in 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)
  
file_path: cupy/cupy/fft/config.py
imports: from cupy import _util
  from cupy.fft._cache import get_plan_cache
  from cupy.fft._cache import clear_plan_cache
  from cupy.fft._cache import get_plan_cache_size
  from cupy.fft._cache import set_plan_cache_size
  from cupy.fft._cache import get_plan_cache_max_memsize
  from cupy.fft._cache import set_plan_cache_max_memsize
  from cupy.fft._cache import show_plan_cache_info
  import sys
label_desc: Use image node_id 1 for calling a global function with example usage: set_cufft_gpus(gpus) without return types