base_model_loss_: Internal function for use by calculate_marginal_vimp
In breather/brightbox: Peek into any blackbox learner (including ensembles)

Calculate baseline accuracy using all variables in training data

1 2	base_model_loss_(method, x, y, resampling_indices, trControl, tuneGrid, loss_metric, ...)

`method`	character string defining method to pass to caret
`x`	data.table containing predictor variables
`y`	vector containing target variable
`resampling_indices`	a list of integer vectors corresponding to the row indices used for each resampling iteration
`trControl`	trainControl object to be passed to caret train.
`tuneGrid`	a data.frame containing hyperparameter values for caret. Should only contain one value for each hyperparameter. Set to NULL if caret method does not have any hyperparameter values.
`loss_metric`	character. Loss metric to evaluate accuracy of model
`...`	additional arguments to pass to caret train