code: def test_csv_serializer_list_of_str(csv_serializer):
      result = csv_serializer.serialize(["1,2,3", "4,5,6"])
  
      assert result == "1,2,3\n4,5,6"
  
imports: from __future__ import absolute_import
  import io
  import json
  import os
  import numpy
  import pytest
  import scipy.sparse
  from sagemaker.serializers import CSVSerializer, NumpySerializer, JSONSerializer, IdentitySerializer, SparseMatrixSerializer, JSONLinesSerializer, LibSVMSerializer, DataSerializer
  from tests.unit import DATA_DIR
label_desc: Use image node_id 6 for calling a global function with example usage: test_csv_serializer_list_of_str(csv_serializer) without return types