fix warning

[geertijewski]

solution by @515orestis #14

[nono303]

Hi,
Thanks @geertijewski for this PR!
with php8 count on uncountable object trigger an error and not a warning
testing var with is_countable before count is now mandatory

[geertijewski]

Hi @nono303 thanks I was not aware of this. However I already removed the invocation of count() and replaced it with is_array(), so unless I missed something I don't think I need to amend this Pull Request

[nono303]

Hi @geertijewski,
you don't need to amend the PR
is_countable is nicer before count but require >=7.3 https://php.watch/versions/7.3#new-is_countable-function