/**
* Lenght: 11
* Formato: 999.999.999-99
* @param string $cpf
* @return string|null
*/
public static function cpf($cpf)
{
if (VALIDAR::cpf($cpf)) {
$cpf = preg_replace('/[^0-9]/', '', $cpf);
return preg_replace('/^([0-9]{3})([0-9]{3})([0-9]{3})([0-9]{2})$/', '$1.$2.$3-$4', $cpf);
}
return null;
}
