code: def test_transformation(self):
      change_sample = trans_method.transform(sample, n=3)
      self.assertEqual(3, len(change_sample))
  
      for s in change_sample:
          self.assertTrue(
              len(s.get_value("x")) > len(sample.get_value("x"))
          )
          self.assertTrue(s.get_value("x") != sample.get_value("x"))
  
imports: import random
  import unittest
  from textflint.input.component.sample import UTCnSample
  from textflint.generation.transformation.UTCN import CnPunctuation
label_desc: Use image node_id 1 for calling the TestPunctuation obj's underlying member method code with example usage: obj.test_transformation() without return types