code: def init(use_mpi=False):
      def run_init(rank, use_mpi=False):
          dev = cuda.Device(rank)
          dev.use()
          comm = init_process_group(N_WORKERS, rank, use_mpi=use_mpi)
          # Do a simple call to verify we got a valid comm
          in_array = cupy.zeros(1)
          if rank == 0:
              in_array = in_array + 1
          comm.broadcast(in_array, 0)
          testing.assert_allclose(in_array, cupy.ones(1))
  
      if use_mpi:
          from mpi4py import MPI
  
          # This process was run with mpiexec
          run_init(MPI.COMM_WORLD.Get_rank(), dtype, True)
          run_init(MPI.COMM_WORLD.Get_rank(), dtype, True)
      else:
          _launch_workers(run_init)
  
imports: import sys
  import time
  import warnings
  import cupy
  from cupy import cuda
  from cupy.cuda import nccl
  from cupy import testing
  from cupyx.distributed import init_process_group
  from cupyx.distributed._nccl_comm import NCCLBackend
  from cupyx.distributed._store import ExceptionAwareProcess
  from cupyx.scipy import sparse
label_desc: Use image node_id 13 for calling a global function with example usage: init(use_mpi) without return types