code: def test_multi_timeseries_variable_ts_length_sunny_day(self):
      data = [
          constant_timeseries(value=123, length=10),
          constant_timeseries(value=123, length=100),
          constant_timeseries(value=123, length=1000),
      ]
      train_set, test_set = train_test_split(
          data,
          axis=1,
          test_size=2,
          input_size=1,
          horizon=2,
          vertical_split_type=MODEL_AWARE,
      )
      train_lengths = [len(ts) for ts in train_set]
      test_lengths = [len(ts) for ts in test_set]
  
      assert train_lengths == [7, 97, 997] and test_lengths == [
          4,
          4,
          4,
      ], "Wrong shapes: training set shape: {}; test set shape {}".format(
          train_lengths, test_lengths
      )
  
imports: import pytest
  from darts.utils.model_selection import MODEL_AWARE, SIMPLE, train_test_split
  from darts.utils.timeseries_generation import constant_timeseries
label_desc: Use image node_id 19 for calling the TestClassTrainTestSplit obj's underlying member method code with example usage: obj.test_multi_timeseries_variable_ts_length_sunny_day() without return types