code: def test_selected_columns(self):
      test_cont = (
          pd.DataFrame(
              [
                  [0.0, 1, 0.0, "a"],
                  [0.5, 2, 0.5, "b"],
                  [1.0, 3, 1.0, "c"],
              ],
          )
          .astype(dtype={1: "O", 3: "O"})
          .values
      )
      transformer_cont2 = StaticCovariatesTransformer(
          cols_num=["cont1", "cont2"], cols_cat=[]
      )
      self.helper_test_scaling(
          self.series1, transformer_cont2, test_cont
      )
  
      test_contcat = (
          pd.DataFrame(
              [
                  [0.0, 1, 0.0, 0.0],
                  [1.0, 2, 0.5, 1.0],
                  [2.0, 3, 1.0, 2.0],
              ],
          )
          .astype(dtype={1: "O"})
          .values
      )
      transformer_contcat = StaticCovariatesTransformer(
          cols_num=["cont2"], cols_cat=["cat2"]
      )
      self.helper_test_scaling(
          self.series1, transformer_contcat, test_contcat
      )
  
      test_cat = pd.DataFrame(
          [
              [0.0, 0.0, 0.1, 0.0],
              [1.0, 1.0, 0.2, 1],
              [2.0, 2.0, 0.3, 2.0],
          ],
      ).values
      transformer_cat = StaticCovariatesTransformer(
          cols_num=[], cols_cat=["cat1", "cat2"]
      )
      self.helper_test_scaling(self.series1, transformer_cat, test_cat)
  
file_path: darts/darts/tests/dataprocessing/transformers/test_static_covariates_transformer.py
imports: import numpy
  import pandas
  import pytest
  from sklearn.preprocessing import MinMaxScaler, OneHotEncoder
  from darts import TimeSeries
  from darts.dataprocessing.transformers import StaticCovariatesTransformer
  from darts.utils import timeseries_generation
label_desc: Use image node_id 3 for calling the TestStaticCovariatesTransformer obj's underlying member method code with example usage: obj.test_selected_columns() without return types