code: def test_index(self):
      self.o.ind = -2
      self.n.ind = 2
      self.assertEqual(self.seq[self.n], self.seq[2])
      self.assertEqual(self.seq[self.o], self.seq[-2])
  
imports: import unittest
  from test import support
  import operator
label_desc: Use image node_id 2 for calling the SeqTestCase obj's underlying member method code with example usage: obj.test_index() without return types