code: def test_drop_1_variable(df_vartypes):
      transformer = DropFeatures(features_to_drop="City")
      X = transformer.fit_transform(df_vartypes)
  
      # expected result
      df = pd.DataFrame(
          {
              "Name": ["tom", "nick", "krish", "jack"],
              "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"),
          }
      )
  
      # init params
      assert transformer.features_to_drop == "City"
  
      # transform params
      assert X.shape == (4, 4)
      assert type(X) == pd.DataFrame
      pd.testing.assert_frame_equal(X, df)
  
file_path: feature_engine/tests/test_selection/test_drop_features.py
imports: import pandas
  import pytest
  from feature_engine.selection import DropFeatures
label_desc: Use image node_id 1 for calling a global function with example usage: test_drop_1_variable(df_vartypes) without return types