/**
 * Checks if the value is not a substring of the target.
 * If given value is not a string, then it returns false.
 *
 * @param value The value being checked.
 * @param target The target value to perform the check against.
 * @return True if the value is a not a substring of the target, false otherwise.
 */
export declare function isNotSubString(value: string, target: string): boolean;