code: def test_main(self):
      try:
          ppdet.model_zoo.list_model(self._filter)
          self.assertTrue(True)
      except:
          self.assertTrue(False)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import unittest
  import ppdet
label_desc: Use image node_id 2 for calling the TestListModel obj's underlying member method code with example usage: obj.test_main() without return types