class Foo
{
    public function doSomething($number)
    {
        if (!is_int($number)) {
            throw new InvalidArgumentException('Argument is not an integer');
        }
        
        if ($number > 10) {
            echo 'Number is bigger than 10';
        } elseif ($number < 10) {
            echo 'Number is smaller than 10';
        } else {
            echo 'Number is equal to 10';
        }
    }
}

$foo = new Foo();
$foo->doSomething(100);