code: def all_reduce(cls, comm, in_array, out_array, op="sum", stream=None):
      comm._check_contiguous(in_array)
      comm._check_contiguous(out_array)
      stream = comm._get_stream(stream)
      dtype, count = _get_nccl_dtype_and_count(in_array)
      op = comm._get_op(op, in_array.dtype.char)
      comm._comm.allReduce(
          in_array.data.ptr,
          out_array.data.ptr,
          count,
          dtype,
          op,
          stream,
      )
  
imports: import numpy
  import warnings
  import cupy
  from cupy.cuda import nccl
  from cupyx.distributed import _store
  from cupyx.distributed._comm import _Backend
  from cupyx.scipy import sparse
label_desc: Use image node_id 1 for calling the _DenseNCCLCommunicator obj's underlying member method code with example usage: obj.all_reduce(cls, comm, in_array, out_array, op, stream) without return types