Consider the use of "instanceof" instead of "get_class"

[samag]

Looking at

// If given date is a DateTime object; check if it falls in the weekend
if (get_class($date) === 'DateTime') {
    if (in_array($date->format('w'), $this->weekend_days)) {
        return false;
    }
}

the condition fails for any subclasses of DateTime (like the very popular Carbon class) which needlessly limits your APIs scope. Please consider the instanceof operator to allow for classes that derive from DateTime.

[stelgenhof]

It does seem indeed a better way to verify the class with the instanceof operator. Thanks for the suggestion!

[stelgenhof]

Resolved.