Update voc.py

paddlex/cv/datasets/voc.py

@@ -72,7 +72,7 @@ class VOCDetection(Dataset):
         label_id = 1
         with open(label_list, 'r', encoding=get_encoding(label_list)) as fr:
             for line in fr.readlines():
-                cname2cid[line.strip()]] = label_id
+                cname2cid[line.strip()] = label_id
                 label_id += 1
                 self.labels.append(line.strip())
         logging.info("Starting to read file list from dataset...")