public async Task <ExternalRegisterUserDto> GetExternalData(IExternalDataDto externalData)
{
if (!(externalData is FacebookExternalDataDto facebookExternalData))
{
throw new ArgumentNullException(nameof(facebookExternalData));
}
var facebookUserDto = await _facebookClient.GetFacebookUserData(facebookExternalData.AccessToken);
var result = _mapper.Map <ExternalRegisterUserDto>(facebookUserDto);
return(result);
}