regression.recipe_func: Either NULL (default) or a function that that takes in a recipes::recipe()
object and returns a modified recipes::recipe() with potentially additional recipe steps. See the regression vignette for several examples. Note, to make it easier to call explain() from Python, the regression.recipe_func can also be a string containing an R function. For example, "function(recipe) return(recipes::step_ns(recipe,recipes::all_numeric_predictors(), deg_free = 2))" is also a valid input. It is essential to include the package prefix if the package is not loaded.
x_explain: Data.table with the features of the observation whose predictions ought to be explained (test data).