example tasks

[m-muecke]

• for now don't add data and just tsbox to transform Airpassengers and other sample data

• end goal would be to add a function for downloading and parsing the Monash Time Series Forecasting Repository, but perhaps this should be added as an extension package similar to mlr3oml or like done with tsibbledata: https://github.com/tidyverts/tsibbledata/blob/4fd00371775bbe164b54f32ee0ff361f5f2b293e/R/forecastingdata_org.R#L100

• air passengers

• need some good multivariate or some other famous dataset

[m-muecke]

There are good sample tasks in {tsibbledata}, but they're quite Australia specific