code: def test_get_tokens(self):
      self.assertEqual(
          ["今", "天", "天", "气", "很", "好", "。"], sample.get_tokens("x")
      )
      new_sample = UTCnSample({"x": ""})
      self.assertEqual([], new_sample.get_tokens("x"))
  
imports: import unittest
  from textflint.input.component.sample.utcn_sample import *
label_desc: Use image node_id 6 for calling the TestUTCnSample obj's underlying member method code with example usage: obj.test_get_tokens() without return types