code: def test_distributor_map_reduce_is_called(self):
      df = self.create_test_data_sample()
  
      mock = Mock(spec=IterableDistributorBaseClass)
      mock.close.return_value = None
      mock.map_reduce.return_value = []
  
      X = extract_features(
          timeseries_container=df,
          column_id="id",
          column_sort="sort",
          column_kind="kind",
          column_value="val",
          default_fc_parameters=self.name_to_param,
          distributor=mock,
      )
  
      self.assertTrue(mock.map_reduce.called)
  
imports: import os
  import tempfile
  import numpy
  import pandas
  from mock import Mock
  from tests.fixtures import DataTestCase
  from tsfresh.feature_extraction.extraction import extract_features
  from tsfresh.feature_extraction.settings import ComprehensiveFCParameters, PickableSettings
  from tsfresh.utilities.distribution import IterableDistributorBaseClass, MapDistributor
label_desc: Use image node_id 2 for calling the DistributorUsageTestCase obj's underlying member method code with example usage: obj.test_distributor_map_reduce_is_called() without return types