How can the "count()" function be modified to simulate the old PHP5 behavior in order to fix the error?

The issue arises when using the "count()" function in PHP7+ where it now throws a warning when counting non-countable objects. To simulate the old PHP5 behavior and fix the error, you can modify the "count()" function by checking if the object is countable using the "is_countable()" function before counting it.

function customCount($obj) {
    if (is_countable($obj)) {
        return count($obj);
    } else {
        return 0;
    }
}

// Example usage
$obj = [1, 2, 3];
echo customCount($obj); // Output: 3