def get_concepts(gt_concepts, ex_index, num_samples):
    """ Given [(gt_concept, start_i, end_i)...]
        Return the ground truth occuring at a given index."""

    gt_concept = None
    for gt_c, s_i, e_i in gt_concepts:
        if s_i <= ex_index < e_i:
            gt_concept = gt_c
            break
    return (gt_concept)