text: """
  Support for Google Home bluetooth tacker.
  
  For more details about this platform, please refer to the documentation at
  https://home-assistant.io/components/device_tracker.googlehome/
  """
  import logging
  
  import voluptuous as vol
  
  import homeassistant.helpers.config_validation as cv
  from homeassistant.helpers.aiohttp_client import async_get_clientsession
  from homeassistant.components.device_tracker import (
      DOMAIN, PLATFORM_SCHEMA, DeviceScanner)
  from homeassistant.const import CONF_HOST
  
  REQUIREMENTS = ['ghlocalapi==0.1.0']
  
  _LOGGER = logging.getLogger(__name__)
  
  CONF_RSSI_THRESHOLD = 'rssi_threshold'
  
  PLATFORM_SCHEMA = vol.All(
      PLATFORM_SCHEMA.extend({
          vol.Required(CONF_HOST): cv.string,
          vol.Optional(CONF_RSSI_THRESHOLD, default=-70): vol.Coerce(int),
      }))
  
  
  async def async_get_scanner(hass, config):
      """Validate the configuration and return an Google Home scanner."""
      scanner = GoogleHomeDeviceScanner(hass, config[DOMAIN])
      await scanner.async_connect()
      return scanner if scanner.success_init else None
  
  
  class GoogleHomeDeviceScanner(DeviceScanner):
      """This class queries a Google Home unit."""
  
      def __init__(self, hass, config):
          """Initialize the scanner."""
          from ghlocalapi.device_info import DeviceInfo
          from ghlocalapi.bluetooth import Bluetooth
  
          self.last_results = {}
  
          self.success_init = False
          self._host = config[CONF_HOST]
          self.rssi_threshold = config[CONF_RSSI_THRESHOLD]
  
          session = async_get_clientsession(hass)
          self.deviceinfo = DeviceInfo(hass.loop, session, self._host)
          self.scanner = Bluetooth(hass.loop, session, self._host)
  
      async def async_connect(self):
          """Initialize connection to Google Home."""
          await self.deviceinfo.get_device_info()
          data = self.deviceinfo.device_info
          self.success_init = data is not None
  
      async def async_scan_devices(self):
          """Scan for new devices and return a list with found device IDs."""
          await self.async_update_info()
          return list(self.last_results.keys())
  
      async def async_get_device_name(self, device):
          """Return the name of the given device or None if we don't know."""
          if device not in self.last_results:
              return None
          return '{}_{}'.format(self._host,
                                self.last_results[device]['btle_mac_address'])
  
      async def get_extra_attributes(self, device):
          """Return the extra attributes of the device."""
          return self.last_results[device]
  
      async def async_update_info(self):
          """Ensure the information from Google Home is up to date."""
          _LOGGER.debug('Checking Devices...')
          await self.scanner.scan_for_devices()
          await self.scanner.get_scan_result()
          ghname = self.deviceinfo.device_info['name']
          devices = {}
          for device in self.scanner.devices:
              if device['rssi'] > self.rssi_threshold:
                  uuid = '{}_{}'.format(self._host, device['mac_address'])
                  devices[uuid] = {}
                  devices[uuid]['rssi'] = device['rssi']
                  devices[uuid]['btle_mac_address'] = device['mac_address']
                  devices[uuid]['ghname'] = ghname
                  devices[uuid]['source_type'] = 'bluetooth'
          self.last_results = devices
  