for decoder_idx, (cls, reg) in enumerate(zip(cls_scores, reg_preds)):

    #cls_scores list6 every [1,900,10]  reg_preds list6，[1,900,11] 
    @force_fp32(apply_to=('cls_scores', 'reg_preds'))
    def loss(self, cls_scores, reg_preds, data, feature_maps=None):
        output = {} #cls [1,900,10]  reg [1,900,11]   #cls_scores list6 every [1,900,10]  reg_preds list6，[1,900,11] 
        for decoder_idx, (cls, reg) in enumerate(zip(cls_scores, reg_preds)): 
            pass