Drop irrelevant predictions
filter_predictions(predictions, forecast_type, incidence_period, signal)
| predictions | Dataframe as produced by  | 
|---|---|
| forecast_type | "quantile", "point", or both | 
| incidence_period | "epiweek", "day", or both | 
| signal | Any combination of "confirmed_incidence_num", "deaths_incidence_num", "deaths_cumulative_num", and/or "confirmed_admissions_covid_1d". | 
predictions dataframe with irrelevant rows removed