public async Task <string> GetAccessToken()
        {
            var refreshToken = await _oAuthService.GetWithingsRefreshToken();

            var newTokens = await _withingsClient.GetTokensByRefreshToken(refreshToken);

            await _oAuthService.SaveWithingsAccessToken(newTokens.access_token);

            await _oAuthService.SaveWithingsRefreshToken(newTokens.refresh_token);

            return(newTokens.access_token);
        }