code: def test_is_active(self):
      ts = graphlib.TopologicalSorter()
      ts.add(1, 2)
      ts.prepare()
  
      self.assertTrue(ts.is_active())
      self.assertEqual(ts.get_ready(), (2,))
      self.assertTrue(ts.is_active())
      ts.done(2)
      self.assertTrue(ts.is_active())
      self.assertEqual(ts.get_ready(), (1,))
      self.assertTrue(ts.is_active())
      ts.done(1)
      self.assertFalse(ts.is_active())
  
imports: import graphlib
  import os
  import unittest
  from test.support.script_helper import assert_python_ok
label_desc: Use image node_id 14 for calling the TestTopologicalSort obj's underlying member method code with example usage: obj.test_is_active() without return types