remove unnecessary import

custom_components/mass/__init__.py

@@ -8,7 +8,7 @@
 
 from homeassistant.config_entries import ConfigEntry, ConfigEntryState
 from homeassistant.const import CONF_URL, EVENT_HOMEASSISTANT_STOP, Platform
-from homeassistant.core import Event, HomeAssistant, DOMAIN as HOMEASSISTANT_DOMAIN
+from homeassistant.core import Event, HomeAssistant
 from homeassistant.exceptions import ConfigEntryNotReady
 from homeassistant.helpers import config_validation as cv
 from homeassistant.helpers import device_registry as dr