code: def test_inverse_transform_unknown_token(self):
      x_train, y_train = [["a", "b"]], [["X", "O"]]
      it = IndexTransformer()
      it.fit(self.x, self.y)
      _, y = it.transform(x_train, y_train)
      inv_y = it.inverse_transform(y)
      self.assertNotEqual(inv_y, self.y)
  
imports: import os
  import shutil
  import unittest
  import numpy
  from anago.preprocessing import IndexTransformer, pad_nested_sequences
label_desc: Use image node_id 11 for calling the TestIndexTransformer obj's underlying member method code with example usage: obj.test_inverse_transform_unknown_token() without return types