Because of the `toString()` [here](https://github.com/mapbox/cloudfriend/blob/75fa1750e9330aecdd86edeb625fc3a83a4eb266/lib/intrinsic.js#L206), if you pass a object (e.g. a `"Ref"`) to `cf.split()`, it gets turned into `[object Object]`. ```js > cf.split(',', cf.ref('SomeParameter')) { 'Fn::Split': [ ',', '[object Object]' ] } ``` cc @xrwang
