src/transformers/models/detr/modeling_detr.py/DetrHungarianMatcher/__init__
class DetrHungarianMatcher:    def __init__(self, class_cost: float = 1, bbox_cost: float = 1, giou_cost: float = 1):
        """
        Creates the matcher.

        Params:
            class_cost: This is the relative weight of the classification error in the matching cost
            bbox_cost: This is the relative weight of the L1 error of the bounding box coordinates in the matching cost
            giou_cost: This is the relative weight of the giou loss of the bounding box in the matching cost
        """
        super().__init__()

        requires_backends(self, ["scipy"])

        self.class_cost = class_cost
        self.bbox_cost = bbox_cost
        self.giou_cost = giou_cost
        assert class_cost != 0 or bbox_cost != 0 or giou_cost != 0, "All costs of the Matcher can't be 0"