I have followed a 3rd party tutorial on IOS Charts (How to Use iOS Charts API to Create Beautiful Charts in Swift)
IOS charts tutorial
and everything works fine for the demo app and also creating a chart app from scratch.
However I also have a working app and I am trying to add a graph to it but when I add the embedded binaries to my working app, my project will no longer build and I get the error message...
clang: error: linker command failed with exit code 1 (use -v to see invocation)
I had convert my working app to Swift 3 via edit > convert > To current swift syntax in order to use IOS charts. It now works perfectly.