src/transformers/models/deta/modeling_deta.py/DetaStage2Assigner/__init__
class DetaStage2Assigner:    def __init__(self, num_queries, max_k=4):
        super().__init__()
        self.positive_fraction = 0.25
        self.bg_label = 400  # number > 91 to filter out later
        self.batch_size_per_image = num_queries
        self.proposal_matcher = DetaMatcher(thresholds=[0.6], labels=[0, 1], allow_low_quality_matches=True)
        self.k = max_k