public function verifyEmailIdentity($email)
    {
        $this->_action = 'VerifyEmailIdentity';
        $this->_method = 'GET';
        $this->_refreshDate();

        if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
            throw new Exception('Invalid email');
            return;
        }

        $parameters = array(
            'EmailAddress' => $email
        );

        $this->_generateSignature($parameters);
        $res = $this->_request();
        if ($res['code'] == 200) {
            return (string) $res['body']->ResponseMetadata->RequestId;
        } else {
            return new SimpleEmailServiceError((string) $res['body']->Error->Code);
        }
    }