How to check in IDApython that if a call is an API/Library call or not?

I want to check for every call instruction whether its an API call or library call (statically linked that flirt recognized)

The only solution i found is this :

Finding all API calls in a function

but it seems to not work some times and a lot of redundant code in there, and sometimes it recognizes dword calls as library calls for some reason like call dword_xxxx or call unk_xxx

there has to be a simpler way to just check if a call is a library call or not, anyone knows how?