In the book by Marcus Geduld "AfterEffectsExpressions" there is an example (p.145) that reads:
effect("4-Color Gradient").param(propertyIndex - 2).valueAtTime(time - .5)
This is an expression applied to one of the points in a 4-Color Gradient effect. It returns an error message:
Bad method arguments: propertyIndex can't be used in this Property. It seems odd that this book has a whole section that uses this expression that is apparently not valid.
BTW I have found a number of typos in the book which otherwise I enjoy and have learned plenty from. I would contact him if there was some link in his book but I find none.If someone can figure this one out I would really appreciate it.