code: def test_drop_constant_features_with_list_of_variables(
      df_constant_features,
  ):
      # test case 3: drop features showing threshold more than 0.7 with variable list
      transformer = DropConstantFeatures(
          tol=0.7,
          variables=["Name", "const_feat_num", "quasi_feat_num"],
      )
      X = transformer.fit_transform(df_constant_features)
  
      # expected result
      df = pd.DataFrame(
          {
              "Name": ["tom", "nick", "krish", "jack"],
              "City": ["London", "Manchester", "Liverpool", "Bristol"],
              "Age": [20, 21, 19, 18],
              "Marks": [0.9, 0.8, 0.7, 0.6],
              "dob": pd.date_range("2020-02-24", periods=4, freq="T"),
              "const_feat_cat": ["a", "a", "a", "a"],
              "quasi_feat_cat": ["a", "a", "a", "b"],
          }
      )
  
      # fit attr
      assert transformer.features_to_drop_ == [
          "const_feat_num",
          "quasi_feat_num",
      ]
  
      # transform params
      pd.testing.assert_frame_equal(X, df)
  
file_path: feature_engine/tests/test_selection/test_drop_constant_features.py
imports: import numpy
  import pandas
  import pytest
  from feature_engine.selection import DropConstantFeatures
label_desc: Use image node_id 4 for calling a global function with example usage: test_drop_constant_features_with_list_of_variables(df_constant_features) without return types