Historical observations, oldest first. At most 15360 points are used; longer histories are truncated to the most recent window. Gaps are rejected rather than filled — decide how to handle a missing observation before asking for a forecast.
ISO dates aligned one-to-one with values. When supplied, forecast rows are dated by extending the series frequency.
Named covariates known only over the history. Each must have the same length as values.
Named covariates known over history and forecast window, such as a calendar or a published projection. Each must have length len(values) + horizon.