new_contents: import six
  from six import u
  from banyan import SortedSet
  import unittest_rand_gen_state
  
  
  @six.with_metaclass(unittest_rand_gen_state.Saver)
  class UnittestBase(object):
      pass
  
  
  class StringTestBase(object):
      def test_construct_bytes(self):
          with self.assertRaises(TypeError):
              t = SortedSet([u('0'), u('3'), u('1')], key_type=six.binary_type)
          t = SortedSet([b'0', b'3', b'1'], key_type=six.binary_type)
          assert b'0' in t
  
      def test_construct_unicode(self):
          with self.assertRaises(TypeError):
              t = SortedSet([b'0', b'3', b'1'], key_type=six.text_type)
          t = SortedSet([u('0'), u('3'), u('1')], key_type=six.text_type)
          assert u('0') in t
  
subject: use testbase that is cross-platform