External function to delete a course

 public static function delete_courses_by_id_parameters() {

        return new external_function_parameters(

            array(

                'courseids' => new external_multiple_structure(new external_value(PARAM_INT, 'course ID')),

            )

        );

    }

    public static function delete_courses_by_id($courseids) {

        global $CFG, $DB, $USER;

        require_once($CFG->dirroot."/course/lib.php");

        // Ensure the current user is allowed to run this function

        $context = get_context_instance(CONTEXT_SYSTEM);

        require_capability('moodle/course:delete', $context);

        self::validate_context($context);

        $params = self::validate_parameters(self::delete_courses_by_id_parameters(), array('courseids'=>$courseids));

        $transaction = $DB->start_delegated_transaction();

        foreach ($params['courseids'] as $courseid) {

            $course = $DB->get_record('course', array('id'=>$courseid), '*', MUST_EXIST);

            delete_course($courseid,false);

        }

        $transaction->allow_commit();

        return null;

    }

   /**

     * Returns description of method result value

     * @return external_description

     */

    public static function delete_courses_by_id_returns() {

        return null;

    }