code: def test_multi_grid(self):
      size = 2**5 - 1  # test odd size
      freq = 1 / size
      input1 = np.cos(np.arange(size) * 2 * np.pi * freq)
      input2 = np.sin(
          np.arange(size) * 2 * np.pi * freq
      ) + 0.1 * np.random.random(size=size)
  
      series1 = _series_from_values(input1)
      series2 = _series_from_values(input2)
  
      exact_distance = dtw.dtw(
          series1, series2, multi_grid_radius=-1
      ).distance()
      approx_distance = dtw.dtw(
          series1, series2, multi_grid_radius=1
      ).distance()
  
      assert round(abs(exact_distance - approx_distance), 3) == 0
  
imports: import matplotlib.pyplot
  import numpy
  import pandas
  import pytest
  from darts.dataprocessing import dtw
  from darts.metrics import dtw_metric, mae, mape
  from darts.timeseries import TimeSeries
  from darts.utils import timeseries_generation
label_desc: Use image node_id 2 for calling the TestDynamicTimeWarping obj's underlying member method code with example usage: obj.test_multi_grid() without return types