Error: Keyword Argument unsupported by function

It means what it says.  The function "contains()" is a primitive function which doesn't accept keyword syntax.  It is called simply by passing in the parameters required (always and exactly two, an array then the value you want to find).  E.G. "contains({1, 2, 3}, 2)" will evaluate to TRUE.

Sadly there's no easy way to tell which OOB functions support keyword syntax and which ones don't - other than, if you get that error, you know it doesn't.

Hi josephh163,

As it is clearly we can make out from reading the error itself that the keywords that you have used inside the contains function is not supported here we need to directly pass the values without passing the keyword arguments and yes as mikes0011 has mentioned that it is not easy to tell which function supports keyword argument and which not, this you only get to know while practicing these type of functions.