def _assertTrueTrue(self, method):
        """
        Perform the positive case test for C{assertTrue} and C{failUnless}.

        @param method: The test method to test.
        """
        for true in [1, True, 'cat', [1,2], (3,4)]:
            result = method(true, "failed on %r" % (true,))
            if result != true:
                self.fail("Did not return argument %r" % (true,))

        Perform the positive case test for C{assertTrue} and C{failUnless}.

        @param method: The test method to test.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_assertions.py