/**
 * Validates if a CEP (Brazilian postal code) is valid.
 *
 * @param {string} cep - The CEP value to be validated.
 * @returns {boolean} True if the CEP is valid, false otherwise.
 *
 * @example
 * ```typescript
 * isValidCep("01310100"); // true
 * isValidCep("01310-100"); // true
 * isValidCep("12345"); // false (invalid length)
 * ```
 */
export declare const isValidCep: (cep: string) => boolean;