diff --git a/mindspore/ccsrc/minddata/dataset/text/kernels/ngram_op.cc b/mindspore/ccsrc/minddata/dataset/text/kernels/ngram_op.cc
index b5240687316..d9b24eae454 100644
--- a/mindspore/ccsrc/minddata/dataset/text/kernels/ngram_op.cc
+++ b/mindspore/ccsrc/minddata/dataset/text/kernels/ngram_op.cc
@@ -59,12 +59,12 @@ Status NgramOp::Compute(const std::shared_ptr<Tensor> &input, std::shared_ptr<Te
     int32_t start_ind = l_len_ - std::min(l_len_, n - 1);
     int32_t end_ind = offsets.size() - r_len_ + std::min(r_len_, n - 1);
     if (end_ind - start_ind <= n) {
-      res.emplace_back(std::string());  // push back empty string
+      (void)res.emplace_back(std::string());  // push back empty string
     } else {
       CHECK_FAIL_RETURN_UNEXPECTED(end_ind - n >= 0, "Ngram: get offsets failed.");
 
       for (int ind = start_ind; ind < end_ind - n; ind++) {
-        res.emplace_back(str_buffer.substr(offsets[ind], offsets[ind + n] - offsets[ind] - separator_.size()));
+        (void)res.emplace_back(str_buffer.substr(offsets[ind], offsets[ind + n] - offsets[ind] - separator_.size()));
       }
     }
   }
@@ -89,7 +89,7 @@ Status NgramOp::OutputShape(const std::vector<TensorShape> &inputs, std::vector<
     // if len_with_padding - n < 0, this would return an empty string
     num_elements += std::max(len_with_padding - n, 0);
   }
-  outputs.emplace_back(TensorShape({num_elements}));
+  (void)outputs.emplace_back(TensorShape({num_elements}));
   CHECK_FAIL_RETURN_UNEXPECTED(outputs.size() == NumOutput(), "Ngram: incorrect num of outputs\n");
   return Status::OK();
 }
diff --git a/mindspore/dataset/engine/datasets.py b/mindspore/dataset/engine/datasets.py
index 444e78f7196..252622e3260 100644
--- a/mindspore/dataset/engine/datasets.py
+++ b/mindspore/dataset/engine/datasets.py
@@ -1752,6 +1752,7 @@ class Dataset:
         """Reset the dataset for next epoch."""
 
     def is_shuffled(self):
+        """Returns True if the dataset or its children is shuffled."""
         for input_dataset in self.children:
             if input_dataset.is_shuffled():
                 return True
@@ -1759,6 +1760,7 @@ class Dataset:
         return False
 
     def is_sharded(self):
+        """Returns True if the dataset or its children is sharded."""
         for input_dataset in self.children:
             if input_dataset.is_sharded():
                 return True
diff --git a/mindspore/lite/micro/example/mnist_stm32f746/mnist_stm32f746/include/lite_utils.h b/mindspore/lite/micro/example/mnist_stm32f746/mnist_stm32f746/include/lite_utils.h
index cf7a4d073fe..ec66f2222a0 100755
--- a/mindspore/lite/micro/example/mnist_stm32f746/mnist_stm32f746/include/lite_utils.h
+++ b/mindspore/lite/micro/example/mnist_stm32f746/mnist_stm32f746/include/lite_utils.h
@@ -149,7 +149,7 @@ class String {
       if (buffer_ == nullptr) {
         MS_C_EXCEPTION("malloc data failed");
       }
-      strncpy(buffer_, other.buffer_ + pos, size_);
+      strncpy_s(buffer_, size_ + 1, other.buffer_ + pos, size_);
       buffer_[size_] = '\0';
     }
   }
@@ -269,7 +269,7 @@ class String {
       MS_C_EXCEPTION("malloc data failed");
     }
     memcpy(tmp, this->buffer_, size_ + 1);
-    strncat(tmp, str.buffer_, str.size_);
+    strncat_s(tmp, new_size + 1, str.buffer_, str.size_);
     tmp[new_size] = '\0';
     free(buffer_);
     buffer_ = tmp;