code: def test_onnxrt_tfidf_vectorizer_strings(self):
      inputi = np.array(
          [
              ["i1", "i1", "i3", "i3", "i3", "i7"],
              ["i8", "i6", "i7", "i5", "i6", "i8"],
          ]
      )
      output = np.array(
          [
              [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
              [0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 1.0],
          ]
      ).astype(np.float32)
  
      ngram_counts = np.array([0, 4]).astype(np.int64)
      ngram_indexes = np.array([0, 1, 2, 3, 4, 5, 6]).astype(np.int64)
      pool_strings = np.array(
          ["i2", "i3", "i5", "i4", "i5", "i6", "i7", "i8", "i6", "i7"]
      )
  
      model = make_model_gen_version(
          make_graph(
              [
                  make_node(
                      "TfIdfVectorizer",
                      ["tokens"],
                      ["out"],
                      mode="TF",
                      min_gram_length=2,
                      max_gram_length=2,
                      max_skip_count=0,
                      ngram_counts=ngram_counts,
                      ngram_indexes=ngram_indexes,
                      pool_strings=pool_strings,
                  )
              ],
              "tfidf",
              [
                  make_tensor_value_info(
                      "tokens", TensorProto.INT64, [None, None]
                  )
              ],
              [
                  make_tensor_value_info(
                      "out", TensorProto.FLOAT, [None, None]
                  )
              ],
          ),
          opset_imports=OPSETS,
      )
  
      oinf = ReferenceEvaluator(model)
      res = oinf.run(None, {"tokens": inputi})
      self.assertEqual(output.tolist(), res[0].tolist())
  
imports: import unittest
  from functools import wraps
  from os import getenv
  import numpy
  from numpy.testing import assert_allclose
  from parameterized import parameterized
  from onnx import ONNX_ML, TensorProto, TypeProto, ValueInfoProto
  from onnx.checker import check_model
  from onnx.defs import onnx_opset_version
  from onnx.helper import make_graph, make_model_gen_version, make_node, make_opsetid, make_tensor, make_tensor_value_info
  from onnx.reference import ReferenceEvaluator
label_desc: Use image node_id 44 for calling the TestReferenceEvaluatorAiOnnxMl obj's underlying member method code with example usage: obj.test_onnxrt_tfidf_vectorizer_strings() without return types