code: def test_categoricalNaming(self):
      train = pd.DataFrame({"city": ["chicago", "st louis"]})
      enc = encoders.RankHotEncoder(use_cat_names=True)
      enc.fit(train)
      tf = enc.transform(train)
      self.assertListEqual(
          ["city_chicago", "city_st louis"], list(tf.columns)
      )
  
file_path: category_encoders/tests/test_rankhot.py
imports: import pandas
  from unittest import TestCase
  import tests.helpers
  import numpy
  import category_encoders
label_desc: Use image node_id 6 for calling the TestRankHotEncoder obj's underlying member method code with example usage: obj.test_categoricalNaming() without return types