Fastai `Learner` adapted for MaskRCNN.
mask_rcnn_learner(dls, model, cbs = NULL, ...)
`Sequence` of `DataLoaders` passed to the `Learner`. The first one will be used for training and the second for validation.
The model to train.
Optional `Sequence` of callbacks.
learner_kwargs: Keyword arguments that will be internally passed to `Learner`.
model