* Replace unicode with six.text_type * Replace xrange() with range() in tests, performances don't matter there * Get StringIO from six * Serializer.print_to_output(): on Python 3, don't encode Unicode to UTF-8 before calling print(). On Python 3, print() expects Unicode strings. This patch was initially generated by the sixer tool using operations: stringio, unicode, xrange. Change-Id: Ifef87e6feac47286f3858800bcd11125f34d4c20