def assertIn(self, member, container, msg=None):
if member not in container:<EOL><INDENT>standardMsg = '<STR_LIT>' % (safe_repr(member), <EOL>safe_repr(container))<EOL>self.fail(self._formatMessage(msg, standardMsg))<EOL><DEDENT>
Just like self.assertTrue(a in b), but with a nicer default message.