code: def test_deseasonalised_values(sp):
      from statsmodels.tsa.seasonal import seasonal_decompose
  
      transformer = Deseasonalizer(sp=sp)
      transformer.fit(y_train)
      actual = transformer.transform(y_train)
  
      r = seasonal_decompose(y_train, period=sp)
      expected = y_train - r.seasonal
      np.testing.assert_array_equal(actual, expected)
  
file_path: sktime/sktime/transformations/series/detrend/tests/test_deseasonalise.py
imports: import numpy
  import pytest
  from sktime.forecasting.tests._config import TEST_SPS
  from sktime.split import temporal_train_test_split
  from sktime.transformations.series.detrend import Deseasonalizer
  from sktime.utils._testing.forecasting import make_forecasting_problem
  from sktime.utils.validation._dependencies import _check_soft_dependencies
label_desc: Use image node_id 1 for calling a global function with example usage: test_deseasonalised_values(sp) without return types