code: def test_inverse_transform_HaveData_ExpectResultReturned(self):
      train = pd.Series(list("abcd")).to_frame("letter")
  
      enc = encoders.BaseNEncoder(base=2)
      result = enc.fit_transform(train)
      inversed_result = enc.inverse_transform(result)
  
      pd.testing.assert_frame_equal(train, inversed_result)
  
imports: import pandas
  from unittest import TestCase
  import numpy
  import category_encoders
label_desc: Use image node_id 2 for calling the TestBaseNEncoder obj's underlying member method code with example usage: obj.test_inverse_transform_HaveData_ExpectResultReturned() without return types