public static function validateCode($courseCode) { $courseCode = trim($courseCode); if (!preg_match("/^[A-Z0-9]{1,10}\$/", $courseCode)) { throw new Exception("Course code can contain capital letters in the range of A-Z, numbers 0-9 and of length 1-10."); } if (CourseFetcher::codeExists($courseCode)) { throw new Exception("Course code already exists on database. Please insert a different one."); } return $courseCode; }