Check to see if a recipe is trained/prepared
Value
A logical which is true if all of the recipe steps have been run
through prep. If no steps have been added to the recipe, TRUE is
returned only if the recipe has been prepped.
Examples
rec <- recipe(Species ~ ., data = iris) |>
  step_center(all_numeric())
rec |> fully_trained()
#> [1] FALSE
rec |>
  prep(training = iris) |>
  fully_trained()
#> [1] TRUE
