get_fit: Fit a learner on training folds and get predictions on...
In benkeser/cvma: Cross-validation-based maximal association

Fit a learner on training folds and get predictions on validation folds

1	get_fit(task, folds, tmpX, Y, sl_control)

`task`	A named list identifying what training_folds to fit the learner on. The function returns predictions from this fit on the remaining folds (i.e., the validation folds).
`folds`	Vector identifying which fold observations fall into.
`tmpX`	A matrix or data.frame of predictors.
`Y`	A matrix or data.frame of outcomes.
`sl_control`	A list with named entries ensemble.fn, optim_risk_fn, weight_fn, cv_risk_fn, family. Available functions can be viewed with `sl_control_options()`. See `?sl_control_options` for more on how users may supply their own functions.