import { Mfk } from './mfk';
export declare class MfkString {
    mfkString: string;
    /**
     * MFK parsed from a string. Default value is an empty object.
     */
    readonly mfk: Mfk;
    readonly isValidMfk: boolean;
    /**
     * construct an MFK String and build an MFK object. Default MFK object is an empty object.
     * @param mfkString string. The constructor will strip out non-digit characters. The string length must be longer than 40.
     */
    constructor(mfkString: string);
}