import { StringRuleChecker } from './string-rule-checker';
import { GuardResult } from '../../core/guard-result';
export declare class StringIsIso639Part1Alpha2 extends StringRuleChecker<{
    type: 'isIso639Part1Alpha2';
}> {
    constructor(rule: {
        type: 'isIso639Part1Alpha2';
    }, value: string);
    /**
     * @override
     */
    exec(): GuardResult;
    private isIso639Part1Alpha2;
}