fix error

coco_metrics.py

@@ -131,10 +131,10 @@ class EvaluateObjectDetection(evaluate.Metric):
         processed_predictions = []
         for pred in predictions:
             processed_pred: _TYPING_PREDICTION = {}
-            for key, val in pred.items():
+            for k, val in pred.items():
                 if isinstance(val, torch.Tensor):
-                    val = pred[key].detach().cpu().tolist()
-                processed_pred[key] = val
+                    val = val.detach().cpu().tolist()
+                processed_pred[k] = val
             processed_predictions.append(processed_pred)
         return processed_predictions