Class C

Lib/test/test_fstring.py:1624–1628

        # Make sure __format__ is being called.
        class C:
            def __format__(self, s):
                return f'FORMAT-{s}'
            def __repr__(self):
                return 'REPR'

        self.assertEqual(f'{C()=}', 'C()=REPR')
        self.assertEqual(f'{C()=!r}', 'C()=REPR')