Test environments local - macOS 10.14.2, R 3.5.0 travis - Ubuntu 14.04.5 LTS, R 3.5.2 rhub - Windows Server 2008 R2 SP1, R-devel, 32/64 bit, R 3.5.2 R CMD check results 0 errors | 0 warnings | 0 notes Reverse dependencies There are no reverse dependencies.