code: def test_call(self):
      def func_a(x):
          return x + 1
  
      b_test_mode = [False]
  
      def func_b(x, test=False):
          b_test_mode[0] = test
          return x + 1
  
      c_test_mode = [False]
      c_hoge_mode = [False]
  
      def func_c(x, test=False, hoge=False):
          c_test_mode[0] = test
          c_hoge_mode[0] = hoge
          return x + 1
  
      def _test_call(seq):
          out = seq(1)
          self.assertEqual(out, 4)
          self.assertFalse(b_test_mode[0])
          self.assertFalse(c_test_mode[0])
          self.assertFalse(c_hoge_mode[0])
  
          out = seq(1, test=True)
          self.assertEqual(out, 4)
          self.assertTrue(b_test_mode[0])
          self.assertTrue(c_test_mode[0])
          self.assertFalse(c_hoge_mode[0])
  
          out = seq(1, test=True, hoge=True)
          self.assertEqual(out, 4)
          self.assertTrue(b_test_mode[0])
          self.assertTrue(c_test_mode[0])
          self.assertTrue(c_hoge_mode[0])
  
          out = seq(1, test=False, hoge=True)
          self.assertEqual(out, 4)
          self.assertFalse(b_test_mode[0])
          self.assertFalse(c_test_mode[0])
          self.assertTrue(c_hoge_mode[0])
  
      _test_call(Sequence(func_a, func_b, func_c))
      _test_call(Sequence(Sequence(func_a, func_b, func_c)))
      _test_call(
          Sequence(Sequence(func_a), Sequence(func_b), Sequence(func_c))
      )
  
imports: import unittest
  from chainerrl.links import Sequence
label_desc: Use image node_id 1 for calling the TestSequence obj's underlying member method code with example usage: obj.test_call() and returns: unknown, unknown, unknown