def METHOD_NAME(self, mock_time: MockTime):
    t0 = mock_time.now()
    dt = 300 * SECOND
    backoff = retry.ExponentialBackoff(
        initial_sleep=SECOND, max_sleep=10 * dt, timeout_at=t0 + dt
    )
    with pytest.raises(MyError):
        for _ in range(9999):
            mock_time.sleep(
                backoff.next_sleep_or_reraise(MyError()).total_seconds()
            )
    assert t0 + dt <= mock_time.now() <= t0 + 2 * dt