code: def test_init_all(self):
      comms = nccl.NcclCommunicator.initAll(1)
      for i, comm in enumerate(comms):
          assert i == comms[i].rank_id()
      for i, comm in enumerate(comms):
          comms[i].destroy()
  
file_path: cupy/tests/cupy_tests/cuda_tests/test_nccl.py
imports: import pickle
  import unittest
  import cupy
  from cupy import cuda
  from cupy.cuda import nccl
  from cupy import testing
label_desc: Use image node_id 4 for calling the TestNCCL obj's underlying member method code with example usage: obj.test_init_all() without return types