Where did the forecast.Holtwinters go in R 3.4.3?

Question

I'm using R Studio based on R 3.4.3. However, when I tried to call the forecast.HoltWinters function, R told me that "could not find function "forecast.HoltWinters"". Inspect the installed package (v8.2) told me that it's true, there is no forecast.HoltWinters. But the manual in https://cran.r-project.org/web/packages/forecast/ clearly stated that forecast.HoltWinters is still available.

I have also tried stats::HoldWinters, but it's working wrong. The code run fine on another computer, but it couldn't run at all on mine. Is there any solution?

Here is the code. Book2.csv has enough data to last more than 3 periods.

dltt <- read.csv("book2.csv", header = TRUE)
dltt.ts <- ts(dltt$Total, frequency=12, start=c(2014,4))
dltt.ts.hw <- HoltWinters(dltt.ts)
library(forecast)
dltt.ts.hw.fc <- forecast.HoltWinters(dltt.ts.hw) //Error as soon as I run this line

Answer 1

Fit a HoltWinters model using the HoltWinters function and then use forecast . Its all in the help for HoltWinters and forecast , namely "The function invokes particular _methods_ which depend on the class of the first argument" . I'll copy the guts of it here:

m <- HoltWinters(co2)
forecast(m)

Note this will call the non-exported forecast.HoltWinters function, which you should never call directly using triple-colon notation as some may suggest.