|string> */ public function rules(): array { return [ 'alert_email' => 'email_array|nullable', 'admin_cc_email' => 'email|nullable', 'alert_threshold' => 'numeric|nullable', 'alert_interval' => 'numeric|nullable', 'audit_warning_days' => 'numeric|nullable', 'due_checkin_days' => 'numeric|nullable', 'audit_interval' => 'numeric|nullable', ]; } }