docstr: This test checks whether calling the scaler twice is calculating new lambdas instead of
  keeping the old ones
docstr_tok: ["This","test","checks","whether","calling","the","scaler","twice","is","calculating","new","lambdas","instead","of","keeping","the","old","ones"]
code: def test_boxcox_multiple_calls_to_fit(self):
      """
      This test checks whether calling the scaler twice is calculating new lambdas instead of
      keeping the old ones
      """
      box_cox = BoxCox()
  
      box_cox.fit(self.sine_series)
      lambda1 = deepcopy(box_cox._fitted_params)[0].tolist()
  
      box_cox.fit(self.lin_series)
      lambda2 = deepcopy(box_cox._fitted_params)[0].tolist()
  
      assert (
          lambda1 != lambda2
      ), "Lambdas should change when the transformer is retrained"
  
file_path: darts/darts/tests/dataprocessing/transformers/test_boxcox.py
imports: from copy import deepcopy
  import numpy
  import pandas
  import pytest
  from darts import TimeSeries
  from darts.dataprocessing.transformers import BoxCox, Mapper
  from darts.utils.timeseries_generation import linear_timeseries, sine_timeseries
label_desc: Use image node_id 5 for calling the TestBoxCox obj's underlying member method code with example usage: obj.test_boxcox_multiple_calls_to_fit() without return types