tscsPlot() can't handle tibble objects

[mattblackwell]

Per an email on the amelia list from Jonathan Zadra, the following code doesn't work:

library(Amelia)
library(tibble)
data(africa)
africa <- as_tibble(africa)
a.out <- amelia(africa, ts = "year", cs = "country")
tscsPlot(a.out, cs = "Burundi", var = "trade")

We get the following error:

Error: Unsupported use of matrix or array for column indexing