final bool didAuthenticate = await auth.authenticate(
          localizedReason: 'Please authenticate to show account balance',
          options: const AuthenticationOptions(useErrorDialogs: false,  bioTmetricOnly = true));
      // ···
    } on PlatformException catch (e) {
      if (e.code == auth_error.notAvailable) {
        // Add handling of no hardware here.
      } else if (e.code == auth_error.notEnrolled) {
        // ...
      } else {
        // ...
      }
    }