text: """Adds config flow for Airly."""
  from airly import Airly
  from airly.exceptions import AirlyError
  import async_timeout
  import voluptuous as vol
  
  from homeassistant import config_entries
  from homeassistant.const import (
      CONF_API_KEY,
      CONF_LATITUDE,
      CONF_LONGITUDE,
      CONF_NAME,
      HTTP_NOT_FOUND,
      HTTP_UNAUTHORIZED,
  )
  from homeassistant.helpers.aiohttp_client import async_get_clientsession
  import homeassistant.helpers.config_validation as cv
  
  from .const import CONF_USE_NEAREST, DOMAIN, NO_AIRLY_SENSORS
  
  
  class AirlyFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
      """Config flow for Airly."""
  
      VERSION = 1
  
      async def async_step_user(self, user_input=None):
          """Handle a flow initialized by the user."""
          errors = {}
          use_nearest = False
  
          websession = async_get_clientsession(self.hass)
  
          if user_input is not None:
              await self.async_set_unique_id(
                  f"{user_input[CONF_LATITUDE]}-{user_input[CONF_LONGITUDE]}"
              )
              self._abort_if_unique_id_configured()
              try:
                  location_point_valid = await test_location(
                      websession,
                      user_input["api_key"],
                      user_input["latitude"],
                      user_input["longitude"],
                  )
                  if not location_point_valid:
                      await test_location(
                          websession,
                          user_input["api_key"],
                          user_input["latitude"],
                          user_input["longitude"],
                          use_nearest=True,
                      )
              except AirlyError as err:
                  if err.status_code == HTTP_UNAUTHORIZED:
                      errors["base"] = "invalid_api_key"
                  if err.status_code == HTTP_NOT_FOUND:
                      errors["base"] = "wrong_location"
              else:
                  if not location_point_valid:
                      use_nearest = True
                  return self.async_create_entry(
                      title=user_input[CONF_NAME],
                      data={**user_input, CONF_USE_NEAREST: use_nearest},
                  )
  
          return self.async_show_form(
              step_id="user",
              data_schema=vol.Schema(
                  {
                      vol.Required(CONF_API_KEY): str,
                      vol.Optional(
                          CONF_LATITUDE, default=self.hass.config.latitude
                      ): cv.latitude,
                      vol.Optional(
                          CONF_LONGITUDE, default=self.hass.config.longitude
                      ): cv.longitude,
                      vol.Optional(
                          CONF_NAME, default=self.hass.config.location_name
                      ): str,
                  }
              ),
              errors=errors,
          )
  
  
  async def test_location(client, api_key, latitude, longitude, use_nearest=False):
      """Return true if location is valid."""
      airly = Airly(api_key, client)
      if use_nearest:
          measurements = airly.create_measurements_session_nearest(
              latitude=latitude, longitude=longitude, max_distance_km=5
          )
      else:
          measurements = airly.create_measurements_session_point(
              latitude=latitude, longitude=longitude
          )
      with async_timeout.timeout(10):
          await measurements.update()
  
      current = measurements.current
  
      return current["indexes"][0]["description"] != NO_AIRLY_SENSORS
  