Class P

tests/lib/test_credentials.py:1497–1504

        first = AccessToken("a", expires_at=1000 + 600)

        class P:
            calls = 0

            def __call__(self, *, force_refresh: bool = False) -> AccessToken:  # noqa: ARG002
                self.calls += 1
                if self.calls == 1:
                    return first
                raise WorkloadIdentityError("backend down")

        provider = P()
        cache = TokenCache(provider, time_source=clock)