text: """A entity class for mobile_app."""
  from homeassistant.config_entries import ConfigEntry
  from homeassistant.const import CONF_WEBHOOK_ID
  from homeassistant.core import callback
  from homeassistant.helpers.device_registry import DeviceEntry
  from homeassistant.helpers.dispatcher import async_dispatcher_connect
  from homeassistant.helpers.entity import Entity
  
  from .const import (
      ATTR_DEVICE_NAME,
      ATTR_SENSOR_ATTRIBUTES,
      ATTR_SENSOR_DEVICE_CLASS,
      ATTR_SENSOR_ICON,
      ATTR_SENSOR_NAME,
      ATTR_SENSOR_TYPE,
      ATTR_SENSOR_UNIQUE_ID,
      DOMAIN,
      SIGNAL_SENSOR_UPDATE,
  )
  from .helpers import device_info
  
  
  def sensor_id(webhook_id, unique_id):
      """Return a unique sensor ID."""
      return f"{webhook_id}_{unique_id}"
  
  
  class MobileAppEntity(Entity):
      """Representation of an mobile app entity."""
  
      def __init__(self, config: dict, device: DeviceEntry, entry: ConfigEntry):
          """Initialize the sensor."""
          self._config = config
          self._device = device
          self._entry = entry
          self._registration = entry.data
          self._sensor_id = sensor_id(
              self._registration[CONF_WEBHOOK_ID], config[ATTR_SENSOR_UNIQUE_ID]
          )
          self._entity_type = config[ATTR_SENSOR_TYPE]
          self.unsub_dispatcher = None
          self._name = f"{entry.data[ATTR_DEVICE_NAME]} {config[ATTR_SENSOR_NAME]}"
  
      async def async_added_to_hass(self):
          """Register callbacks."""
          self.unsub_dispatcher = async_dispatcher_connect(
              self.hass, SIGNAL_SENSOR_UPDATE, self._handle_update
          )
  
      async def async_will_remove_from_hass(self):
          """Disconnect dispatcher listener when removed."""
          if self.unsub_dispatcher is not None:
              self.unsub_dispatcher()
  
      @property
      def should_poll(self) -> bool:
          """Declare that this entity pushes its state to HA."""
          return False
  
      @property
      def name(self):
          """Return the name of the mobile app sensor."""
          return self._name
  
      @property
      def device_class(self):
          """Return the device class."""
          return self._config.get(ATTR_SENSOR_DEVICE_CLASS)
  
      @property
      def device_state_attributes(self):
          """Return the device state attributes."""
          return self._config[ATTR_SENSOR_ATTRIBUTES]
  
      @property
      def icon(self):
          """Return the icon to use in the frontend, if any."""
          return self._config[ATTR_SENSOR_ICON]
  
      @property
      def unique_id(self):
          """Return the unique ID of this sensor."""
          return self._sensor_id
  
      @property
      def device_info(self):
          """Return device registry information for this entity."""
          return device_info(self._registration)
  
      async def async_update(self):
          """Get the latest state of the sensor."""
          data = self.hass.data[DOMAIN]
          try:
              self._config = data[self._entity_type][self._sensor_id]
          except KeyError:
              return
  
      @callback
      def _handle_update(self, data):
          """Handle async event updates."""
          incoming_id = sensor_id(data[CONF_WEBHOOK_ID], data[ATTR_SENSOR_UNIQUE_ID])
          if incoming_id != self._sensor_id:
              return
  
          self._config = data
          self.async_schedule_update_ha_state()
  