diff --git a/test/test_c10d.py b/test/test_c10d.py
index 428280e9430430e36ab24b471c132d6f4dc9fcd2..1046bab6ad14aebe7ac1b29362fc54741f49a84e 100644
--- a/test/test_c10d.py
+++ b/test/test_c10d.py
@@ -17,10 +17,10 @@ from enum import IntEnum, unique
 import os
 import unittest
 import torch
-import torch_npu
 import torch.distributed as c10d
 import torch.distributed as dist
 import torch.multiprocessing as mp
+import torch_npu
 
 from torch_npu.testing.testcase import TestCase, run_tests
 
diff --git a/test/test_npu.py b/test/test_npu.py
index b8f63f24abdfba51a1b89f1f56771ec814e0c6b0..751e9039803041a0b6942080a530ebc8c2616dfe 100644
--- a/test/test_npu.py
+++ b/test/test_npu.py
@@ -91,9 +91,6 @@ class TestNpu(TestCase):
                 return torch.npu.FloatTensor(*size)
 
         def assert_change(comp=1, empty_cache=False, reset_peak=False):
-            # comp > 0: increased
-            # comp = 0: equal
-            # comp < 0: decreased
             new_m = torch_npu.npu.memory_allocated(device)
             new_max_m = torch_npu.npu.max_memory_allocated(device)
             if comp > 0:
diff --git a/torch_npu/distributed/distributed_c10d.py b/torch_npu/distributed/distributed_c10d.py
index bbb894fe18353ade918f5241739ac95ab73f68be..468bbd5ca07b6c83337086274432fe5cd306248b 100644
--- a/torch_npu/distributed/distributed_c10d.py
+++ b/torch_npu/distributed/distributed_c10d.py
@@ -775,7 +775,7 @@ def isend(tensor,
     """
     _check_single_tensor(tensor, "tensor")
     if _rank_not_in_group(group):
-        return
+        return None
 
     if group is None or group is GroupMember.WORLD:
         default_pg = _get_default_group()