code: def test_inertia_refined_ext(self):
      self.data.ta.inertia(refined=True, append=True)
      self.assertIsInstance(self.data, DataFrame)
      self.assertEqual(self.data.columns[-1], "INERTIAr_20_14")
  
imports: from .config import sample_data
  from .context import pandas_ta
  from unittest import skip, TestCase
  from pandas import DataFrame
label_desc: Use image node_id 20 for calling the TestMomentumExtension obj's underlying member method code with example usage: obj.test_inertia_refined_ext() without return types