code: def test_dtype_to_str():
      assert feature.dtype_to_str(np.int64) == "int64"
      assert feature.dtype_to_str(np.uint8) == "uint8"
  
imports: import numpy
  import pytest
  import tensorflow
  from tensorflow_datasets.core.features import feature
  from tensorflow_datasets.core.features import image_feature
  from tensorflow_datasets.core.proto import feature_pb2
label_desc: Use image node_id 9 for calling a global function with example usage: test_dtype_to_str() without return types