use assert[Not]In where appropriate
diff --git a/Lib/test/test_telnetlib.py b/Lib/test/test_telnetlib.py
index cef2fe7..a04bc3f 100644
--- a/Lib/test/test_telnetlib.py
+++ b/Lib/test/test_telnetlib.py
@@ -321,7 +321,7 @@
txt = telnet.read_all()
cmd = nego.seen
self.assertTrue(len(cmd) > 0) # we expect at least one command
- self.assertTrue(cmd[0] in self.cmds)
+ self.assertIn(cmd[0], self.cmds)
self.assertEqual(cmd[1], tl.NOOPT)
self.assertEqual(len(''.join(data[:-1])), len(txt + cmd))
nego.sb_getter = None # break the nego => telnet cycle