Using is_countable to avoid count with null

[peter279k]

Changed log

• Using the is_countable function to ensure passing non-null to the count function.

[freekmurze]

This function isn't available in PHP 7, which this package still supports.

[peter279k]

The feature is available since the PHP 7.3 version is released.

Please look at the reference.

[freekmurze]

You're right! I learned something 🙂

But I still am going to hold off on this as the current code is clear and safe enough.