use assert[Not]IsInstance where appropriate
diff --git a/Lib/test/test_print.py b/Lib/test/test_print.py
index 394a2f1..f53d9c5 100644
--- a/Lib/test/test_print.py
+++ b/Lib/test/test_print.py
@@ -128,11 +128,11 @@
         self.assertEqual(u''.join(buf.buf), 'hi nothing\n')
         buf = Recorder(False)
         print('hi', 'bye', end=u'\n', file=buf)
-        self.assertTrue(isinstance(buf.buf[1], unicode))
-        self.assertTrue(isinstance(buf.buf[3], unicode))
+        self.assertIsInstance(buf.buf[1], unicode)
+        self.assertIsInstance(buf.buf[3], unicode)
         del buf.buf[:]
         print(sep=u'x', file=buf)
-        self.assertTrue(isinstance(buf.buf[-1], unicode))
+        self.assertIsInstance(buf.buf[-1], unicode)
 
 
 def test_main():