## Test environments
* local Arch linux install, R 3.6.1
* Travis: Ubuntu Xenial (devel, release, and old-release)
* Travis: MacOS 10.13.3 (devel, release, and old-release)
* win-builder (release, and old-release)
* R-hub: Windows (devel)

## R CMD check results
There were no ERRORs or WARNINGs or NOTEs.