How to use the aiohue.RequestError function in aiohue

async def test_flow_link_unknown_host(hass):
    """Test config flow ."""
    flow = config_flow.HueFlowHandler()
    flow.hass = hass

    with patch("aiohue.Bridge.create_user", side_effect=aiohue.RequestError):
        result = await flow.async_step_link({})

    assert result["type"] == "form"
    assert result["step_id"] == "link"
    assert result["errors"] == {"base": "linking"}

async def test_flow_link_unknown_host(hass):
    """Test config flow ."""
    flow = hue.HueFlowHandler()
    flow.hass = hass

    with patch('aiohue.Bridge.create_user',
               side_effect=aiohue.RequestError):
        result = await flow.async_step_link({})

    assert result['type'] == 'form'
    assert result['step_id'] == 'link'
    assert result['errors'] == {
        'base': 'register_failed'
    }

try:
        with async_timeout.timeout(10):
            # Create username if we don't have one
            if not username:
                device_name = unicode_slug.slugify(
                    hass.config.location_name, max_length=19
                )
                await bridge.create_user(f"home-assistant#{device_name}")

            # Initialize bridge (and validate our username)
            await bridge.initialize()

        return bridge
    except (aiohue.LinkButtonNotPressed, aiohue.Unauthorized):
        raise AuthenticationRequired
    except (asyncio.TimeoutError, aiohue.RequestError):
        raise CannotConnect
    except aiohue.AiohueException:
        LOGGER.exception("Unknown Hue linking error occurred")
        raise AuthenticationRequired