code: def test_empty_list(self):
      mock_ts_data = Mock()
      mock_ts_data.df_id_type = str
  
      return_df = PartitionedTsData.pivot(mock_ts_data, [])
  
      self.assertEqual(len(return_df), 0)
      self.assertEqual(len(return_df.index), 0)
      self.assertEqual(len(return_df.columns), 0)
  
imports: import math
  from unittest import TestCase
  from unittest.mock import Mock
  import numpy
  import pandas
  from dask import dataframe
  from tests.fixtures import DataTestCase
  from tsfresh.feature_extraction.data import LongTsFrameAdapter, PartitionedTsData, TsDictAdapter, WideTsFrameAdapter, to_tsdata
  from tsfresh.utilities.distribution import MultiprocessingDistributor
label_desc: Use image node_id 1 for calling the PivotListTestCase obj's underlying member method code with example usage: obj.test_empty_list() without return types