code: def test_hierarchy_preserved_after_predict(self):
      assert self.pred.hierarchy == self.series.hierarchy
  
file_path: darts/darts/tests/dataprocessing/transformers/test_reconciliation.py
imports: import numpy
  from pandas import date_range
  from darts import TimeSeries, concatenate
  from darts.dataprocessing.transformers.reconciliation import BottomUpReconciliator, MinTReconciliator, TopDownReconciliator, _get_summation_matrix
  from darts.models import LinearRegressionModel
  from darts.utils import timeseries_generation
label_desc: Use image node_id 7 for calling the TestReconciliation obj's underlying member method code with example usage: obj.test_hierarchy_preserved_after_predict() without return types