Argh, I just posted the same question due to the same issue. I guess I shouldn’t have started with 5.3 
I was thinking of learning how to create the function in C++ and while I got as far as getting the block into Blueprints I thought there must be a simpler way.
Spinning through the commits in github it seems like that file was last updated May 19th, before the release of 5.2.1, so maybe its an issue upstream (I don’t really know what I’m looking for though).