code: def test_mutant_charts_for_feature(
      self, mock_call_servo, mock_make_json_formatted_for_single_chart
  ):
      example = self.make_and_write_fake_example()
      serving_bundles = [
          inference_utils.ServingBundle(
              "", "", "classification", "", "", False, "", ""
          )
      ]
      num_mutants = 10
      viz_params = inference_utils.VizParams(
          x_min=1,
          x_max=10,
          examples=[example],
          num_mutants=num_mutants,
          feature_index_pattern=None,
      )
  
      mock_call_servo = lambda _, __: None
      mock_make_json_formatted_for_single_chart = lambda _, __: {}
      charts = inference_utils.mutant_charts_for_feature(
          [example], "repeated_float", serving_bundles, viz_params
      )
      self.assertEqual("numeric", charts["chartType"])
      self.assertEqual(4, len(charts["data"]))
      charts = inference_utils.mutant_charts_for_feature(
          [example], "repeated_int", serving_bundles, viz_params
      )
      self.assertEqual("numeric", charts["chartType"])
      self.assertEqual(2, len(charts["data"]))
      charts = inference_utils.mutant_charts_for_feature(
          [example], "single_int", serving_bundles, viz_params
      )
      self.assertEqual("numeric", charts["chartType"])
      self.assertEqual(1, len(charts["data"]))
      charts = inference_utils.mutant_charts_for_feature(
          [example], "non_numeric", serving_bundles, viz_params
      )
      self.assertEqual("categorical", charts["chartType"])
      self.assertEqual(3, len(charts["data"]))
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import sys
  import numpy
  import tensorflow
  from tensorflow_serving.apis import classification_pb2
  from tensorflow_serving.apis import predict_pb2
  from tensorflow_serving.apis import regression_pb2
  from utils import common_utils
  from utils import inference_utils
  from utils import platform_utils
  from utils import test_utils
label_desc: Use image node_id 15 for calling the InferenceUtilsTest obj's underlying member method code with example usage: obj.test_mutant_charts_for_feature(mock_call_servo, mock_make_json_formatted_for_single_chart) without return types