def get_roidb_and_dataset(dataset_name, proposal_file, ind_range):
    """Get the roidb for the dataset specified in the global cfg. Optionally
    restrict it to a range of indices if ind_range is a pair of integers.
    """
    dataset = JsonDataset(dataset_name)
    if cfg.TEST.PRECOMPUTED_PROPOSALS:
        assert proposal_file, 'No proposal file given'
        roidb = dataset.get_roidb(
            proposal_file=proposal_file,
            proposal_limit=cfg.TEST.PROPOSAL_LIMIT
        )
    else:
        roidb = dataset.get_roidb()

    if ind_range is not None:
        total_num_images = len(roidb)
        start, end = ind_range
        roidb = roidb[start:end]
    else:
        start = 0
        end = len(roidb)
        total_num_images = end

    return roidb, dataset, start, end, total_num_images
Get the roidb for the dataset specified in the global cfg. Optionally
    restrict it to a range of indices if ind_range is a pair of integers.
    
detectron/core/test_engine.py