code: def test_summation_matrix(self):
      np.testing.assert_equal(
          _get_summation_matrix(self.series_complex),
          np.array(
              [
                  [1, 1, 1, 1],
                  [1, 1, 0, 0],
                  [0, 0, 1, 1],
                  [1, 0, 1, 0],
                  [0, 1, 0, 1],
                  [1, 0, 0, 0],
                  [0, 1, 0, 0],
                  [0, 0, 1, 0],
                  [0, 0, 0, 1],
              ]
          ),
      )
  
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 6 for calling the TestReconciliation obj's underlying member method code with example usage: obj.test_summation_matrix() without return types