private void CheckIfIamConfigured()
{
if (_configured) { return; }
throw new ReCaptchaException("ReCaptcha is not configured. Get your site and secret keys from google. And call function ReCaptcha.Configure(publicKey, secretKey), or add the keys to the .config file <add key='recaptcha-public-key' value='...' /><add key='recaptcha-site-key' value='...'/>");
}