text: """Config flow for Ring integration."""
  import logging
  
  from oauthlib.oauth2 import AccessDeniedError, MissingTokenError
  from ring_doorbell import Auth
  import voluptuous as vol
  
  from homeassistant import config_entries, const, core, exceptions
  
  from . import DOMAIN  # pylint: disable=unused-import
  
  _LOGGER = logging.getLogger(__name__)
  
  
  async def validate_input(hass: core.HomeAssistant, data):
      """Validate the user input allows us to connect."""
  
      auth = Auth(f"HomeAssistant/{const.__version__}")
  
      try:
          token = await hass.async_add_executor_job(
              auth.fetch_token, data["username"], data["password"], data.get("2fa"),
          )
      except MissingTokenError:
          raise Require2FA
      except AccessDeniedError:
          raise InvalidAuth
  
      return token
  
  
  class RingConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
      """Handle a config flow for Ring."""
  
      VERSION = 1
      CONNECTION_CLASS = config_entries.CONN_CLASS_CLOUD_POLL
  
      user_pass = None
  
      async def async_step_user(self, user_input=None):
          """Handle the initial step."""
          if self._async_current_entries():
              return self.async_abort(reason="already_configured")
  
          errors = {}
          if user_input is not None:
              try:
                  token = await validate_input(self.hass, user_input)
                  await self.async_set_unique_id(user_input["username"])
  
                  return self.async_create_entry(
                      title=user_input["username"],
                      data={"username": user_input["username"], "token": token},
                  )
              except Require2FA:
                  self.user_pass = user_input
  
                  return await self.async_step_2fa()
  
              except InvalidAuth:
                  errors["base"] = "invalid_auth"
              except Exception:  # pylint: disable=broad-except
                  _LOGGER.exception("Unexpected exception")
                  errors["base"] = "unknown"
  
          return self.async_show_form(
              step_id="user",
              data_schema=vol.Schema({"username": str, "password": str}),
              errors=errors,
          )
  
      async def async_step_2fa(self, user_input=None):
          """Handle 2fa step."""
          if user_input:
              return await self.async_step_user({**self.user_pass, **user_input})
  
          return self.async_show_form(
              step_id="2fa", data_schema=vol.Schema({"2fa": str}),
          )
  
      async def async_step_import(self, user_input):
          """Handle import."""
          if self._async_current_entries():
              return self.async_abort(reason="already_configured")
  
          return await self.async_step_user(user_input)
  
  
  class Require2FA(exceptions.HomeAssistantError):
      """Error to indicate we require 2FA."""
  
  
  class InvalidAuth(exceptions.HomeAssistantError):
      """Error to indicate there is invalid auth."""
  