methodwithvalidation.php

<?php 
function test($number, $text)
{
    if (!is_int($number) || is_null($number)) {
        throw new Exception('invalid argument type $number');
    }

    if (!is_string($text) || is_null($text)) {
        throw new Exception('invalid argumenti type $string');
    }
    //do something
    return str_repeat($text, $number);
}