private function emailsToString($emails) {

		$format = [];

		foreach($emails as $email) {

			if(true === isset($email -> name) && trim($email -> name) !== '') {
				$format[] = sprintf('"%s" <%s>', $email -> name, filter_var($email -> email, FILTER_SANITIZE_EMAIL));
			}
			else {
				$format[] = filter_var($email -> email, FILTER_SANITIZE_EMAIL);
			}
		}

		$emails = implode($format, ',');

		return ('' !== trim($emails)) ? $emails : null;
	}